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提交 00354cfb 编写于 作者: J Jay Vosburgh 提交者： Jeff Garzik
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[PATCH] bonding: documentation update 

Contains general updates (additional configuration info, hopefully
better examples, updated some out of date info, and a bonus pass
through ispell to banish the "paramters.") and info specific to
gratuitous ARP and xmit policy functionality already in 2.6.13-rc2.
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>
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Documentation/networking/bonding.txt
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Linux Ethernet Bonding Driver HOWTO
Latest update: 21 June 2005
Initial release : Thomas Davis <tadavis at lbl.gov>
Corrections, HA extensions : 2000/10/03-15 :
- Willy Tarreau <willy at meta-x.org>
......@@ -11,15 +13,22 @@ Corrections, HA extensions : 2000/10/03-15 :
Reorganized and updated Feb 2005 by Jay Vosburgh
Note :
------
Introduction
============
The Linux bonding driver provides a method for aggregating
multiple network interfaces into a single logical "bonded" interface.
The behavior of the bonded interfaces depends upon the mode; generally
speaking, modes provide either hot standby or load balancing services.
Additionally, link integrity monitoring may be performed.
The bonding driver originally came from Donald Becker's beowulf patches for
kernel 2.0. It has changed quite a bit since, and the original tools from
extreme-linux and beowulf sites will not work with this version of the driver.
The bonding driver originally came from Donald Becker's
beowulf patches for kernel 2.0. It has changed quite a bit since, and
the original tools from extreme-linux and beowulf sites will not work
with this version of the driver.
For new versions of the driver, patches for older kernels and the updated
userspace tools, please follow the links at the end of this file.
For new versions of the driver, updated userspace tools, and
who to ask for help, please follow the links at the end of this file.
Table of Contents
=================
......@@ -30,9 +39,13 @@ Table of Contents
3. Configuring Bonding Devices
3.1 Configuration with sysconfig support
3.1.1 Using DHCP with sysconfig
3.1.2 Configuring Multiple Bonds with sysconfig
3.2 Configuration with initscripts support
3.2.1 Using DHCP with initscripts
3.2.2 Configuring Multiple Bonds with initscripts
3.3 Configuring Bonding Manually
3.4 Configuring Multiple Bonds
3.3.1 Configuring Multiple Bonds Manually
5. Querying Bonding Configuration
5.1 Bonding Configuration
......@@ -56,21 +69,30 @@ Table of Contents
11. Promiscuous mode
12. High Availability Information
12. Configuring Bonding for High Availability
12.1 High Availability in a Single Switch Topology
12.1.1 Bonding Mode Selection for Single Switch Topology
12.1.2 Link Monitoring for Single Switch Topology
12.2 High Availability in a Multiple Switch Topology
12.2.1 Bonding Mode Selection for Multiple Switch Topology
12.2.2 Link Monitoring for Multiple Switch Topology
12.3 Switch Behavior Issues for High Availability
12.2.1 HA Bonding Mode Selection for Multiple Switch Topology
12.2.2 HA Link Monitoring for Multiple Switch Topology
13. Configuring Bonding for Maximum Throughput
13.1 Maximum Throughput in a Single Switch Topology
13.1.1 MT Bonding Mode Selection for Single Switch Topology
13.1.2 MT Link Monitoring for Single Switch Topology
13.2 Maximum Throughput in a Multiple Switch Topology
13.2.1 MT Bonding Mode Selection for Multiple Switch Topology
13.2.2 MT Link Monitoring for Multiple Switch Topology
13. Hardware Specific Considerations
13.1 IBM BladeCenter
14. Switch Behavior Issues
14.1 Link Establishment and Failover Delays
14.2 Duplicated Incoming Packets
14. Frequently Asked Questions
15. Hardware Specific Considerations
15.1 IBM BladeCenter
15. Resources and Links
16. Frequently Asked Questions
17. Resources and Links
1. Bonding Driver Installation
......@@ -86,16 +108,10 @@ the following steps:
1.1 Configure and build the kernel with bonding
-----------------------------------------------
The latest version of the bonding driver is available in the
The current version of the bonding driver is available in the
drivers/net/bonding subdirectory of the most recent kernel source
(which is available on http://kernel.org).
Prior to the 2.4.11 kernel, the bonding driver was maintained
largely outside the kernel tree; patches for some earlier kernels are
available on the bonding sourceforge site, although those patches are
still several years out of date. Most users will want to use either
the most recent kernel from kernel.org or whatever kernel came with
their distro.
(which is available on http://kernel.org). Most users "rolling their
own" will want to use the most recent kernel from kernel.org.
Configure kernel with "make menuconfig" (or "make xconfig" or
"make config"), then select "Bonding driver support" in the "Network
......@@ -103,8 +119,8 @@ device support" section. It is recommended that you configure the
driver as module since it is currently the only way to pass parameters
to the driver or configure more than one bonding device.
Build and install the new kernel and modules, then proceed to
step 2.
Build and install the new kernel and modules, then continue
below to install ifenslave.
1.2 Install ifenslave Control Utility
-------------------------------------
......@@ -147,9 +163,9 @@ default kernel source include directory.
Options for the bonding driver are supplied as parameters to
the bonding module at load time. They may be given as command line
arguments to the insmod or modprobe command, but are usually specified
in either the /etc/modprobe.conf configuration file, or in a
distro-specific configuration file (some of which are detailed in the
next section).
in either the /etc/modules.conf or /etc/modprobe.conf configuration
file, or in a distro-specific configuration file (some of which are
detailed in the next section).
The available bonding driver parameters are listed below. If a
parameter is not specified the default value is used. When initially
......@@ -162,18 +178,18 @@ degradation will occur during link failures. Very few devices do not
support at least miimon, so there is really no reason not to use it.
Options with textual values will accept either the text name
or, for backwards compatibility, the option value. E.g.,
"mode=802.3ad" and "mode=4" set the same mode.
or, for backwards compatibility, the option value. E.g.,
"mode=802.3ad" and "mode=4" set the same mode.
The parameters are as follows:
arp_interval
Specifies the ARP monitoring frequency in milli-seconds. If
ARP monitoring is used in a load-balancing mode (mode 0 or 2),
the switch should be configured in a mode that evenly
distributes packets across all links - such as round-robin. If
the switch is configured to distribute the packets in an XOR
Specifies the ARP link monitoring frequency in milliseconds.
If ARP monitoring is used in an etherchannel compatible mode
(modes 0 and 2), the switch should be configured in a mode
that evenly distributes packets across all links. If the
switch is configured to distribute the packets in an XOR
fashion, all replies from the ARP targets will be received on
the same link which could cause the other team members to
fail. ARP monitoring should not be used in conjunction with
......@@ -182,14 +198,14 @@ arp_interval
arp_ip_target
Specifies the ip addresses to use when arp_interval is > 0.
These are the targets of the ARP request sent to determine the
health of the link to the targets. Specify these values in
ddd.ddd.ddd.ddd format. Multiple ip adresses must be
seperated by a comma. At least one IP address must be given
for ARP monitoring to function. The maximum number of targets
that can be specified is 16. The default value is no IP
addresses.
Specifies the IP addresses to use as ARP monitoring peers when
arp_interval is > 0. These are the targets of the ARP request
sent to determine the health of the link to the targets.
Specify these values in ddd.ddd.ddd.ddd format. Multiple IP
addresses must be separated by a comma. At least one IP
address must be given for ARP monitoring to function. The
maximum number of targets that can be specified is 16. The
default value is no IP addresses.
downdelay
......@@ -207,11 +223,13 @@ lacp_rate
are:
slow or 0
Request partner to transmit LACPDUs every 30 seconds (default)
Request partner to transmit LACPDUs every 30 seconds
fast or 1
Request partner to transmit LACPDUs every 1 second
The default is slow.
max_bonds
Specifies the number of bonding devices to create for this
......@@ -221,10 +239,11 @@ max_bonds
miimon
Specifies the frequency in milli-seconds that MII link
monitoring will occur. A value of zero disables MII link
monitoring. A value of 100 is a good starting point. The
use_carrier option, below, affects how the link state is
Specifies the MII link monitoring frequency in milliseconds.
This determines how often the link state of each slave is
inspected for link failures. A value of zero disables MII
link monitoring. A value of 100 is a good starting point.
The use_carrier option, below, affects how the link state is
determined. See the High Availability section for additional
information. The default value is 0.
......@@ -246,17 +265,31 @@ mode
active. A different slave becomes active if, and only
if, the active slave fails. The bond's MAC address is
externally visible on only one port (network adapter)
to avoid confusing the switch. This mode provides
fault tolerance. The primary option affects the
behavior of this mode.
to avoid confusing the switch.
In bonding version 2.6.2 or later, when a failover
occurs in active-backup mode, bonding will issue one
or more gratuitous ARPs on the newly active slave.
One gratutious ARP is issued for the bonding master
interface and each VLAN interfaces configured above
it, provided that the interface has at least one IP
address configured. Gratuitous ARPs issued for VLAN
interfaces are tagged with the appropriate VLAN id.
This mode provides fault tolerance. The primary
option, documented below, affects the behavior of this
mode.
balance-xor or 2
XOR policy: Transmit based on [(source MAC address
XOR'd with destination MAC address) modulo slave
count]. This selects the same slave for each
destination MAC address. This mode provides load
balancing and fault tolerance.
XOR policy: Transmit based on the selected transmit
hash policy. The default policy is a simple [(source
MAC address XOR'd with destination MAC address) modulo
slave count]. Alternate transmit policies may be
selected via the xmit_hash_policy option, described
below.
This mode provides load balancing and fault tolerance.
broadcast or 3
......@@ -270,7 +303,17 @@ mode
duplex settings. Utilizes all slaves in the active
aggregator according to the 802.3ad specification.
Pre-requisites:
Slave selection for outgoing traffic is done according
to the transmit hash policy, which may be changed from
the default simple XOR policy via the xmit_hash_policy
option, documented below. Note that not all transmit
policies may be 802.3ad compliant, particularly in
regards to the packet mis-ordering requirements of
section 43.2.4 of the 802.3ad standard. Differing
peer implementations will have varying tolerances for
noncompliance.
Prerequisites:
1. Ethtool support in the base drivers for retrieving
the speed and duplex of each slave.
......@@ -333,7 +376,7 @@ mode
When a link is reconnected or a new slave joins the
bond the receive traffic is redistributed among all
active slaves in the bond by intiating ARP Replies
active slaves in the bond by initiating ARP Replies
with the selected mac address to each of the
clients. The updelay parameter (detailed below) must
be set to a value equal or greater than the switch's
......@@ -396,6 +439,60 @@ use_carrier
0 will use the deprecated MII / ETHTOOL ioctls. The default
value is 1.
xmit_hash_policy
Selects the transmit hash policy to use for slave selection in
balance-xor and 802.3ad modes. Possible values are:
layer2
Uses XOR of hardware MAC addresses to generate the
hash. The formula is
(source MAC XOR destination MAC) modulo slave count
This algorithm will place all traffic to a particular
network peer on the same slave.
This algorithm is 802.3ad compliant.
layer3+4
This policy uses upper layer protocol information,
when available, to generate the hash. This allows for
traffic to a particular network peer to span multiple
slaves, although a single connection will not span
multiple slaves.
The formula for unfragmented TCP and UDP packets is
((source port XOR dest port) XOR
((source IP XOR dest IP) AND 0xffff)
modulo slave count
For fragmented TCP or UDP packets and all other IP
protocol traffic, the source and destination port
information is omitted. For non-IP traffic, the
formula is the same as for the layer2 transmit hash
policy.
This policy is intended to mimic the behavior of
certain switches, notably Cisco switches with PFC2 as
well as some Foundry and IBM products.
This algorithm is not fully 802.3ad compliant. A
single TCP or UDP conversation containing both
fragmented and unfragmented packets will see packets
striped across two interfaces. This may result in out
of order delivery. Most traffic types will not meet
this criteria, as TCP rarely fragments traffic, and
most UDP traffic is not involved in extended
conversations. Other implementations of 802.3ad may
or may not tolerate this noncompliance.
The default value is layer2. This option was added in bonding
version 2.6.3. In earlier versions of bonding, this parameter does
not exist, and the layer2 policy is the only policy.
3. Configuring Bonding Devices
......@@ -448,8 +545,9 @@ Bonding devices can be managed by hand, however, as follows.
slave devices. On SLES 9, this is most easily done by running the
yast2 sysconfig configuration utility. The goal is for to create an
ifcfg-id file for each slave device. The simplest way to accomplish
this is to configure the devices for DHCP. The name of the
configuration file for each device will be of the form:
this is to configure the devices for DHCP (this is only to get the
file ifcfg-id file created; see below for some issues with DHCP). The
name of the configuration file for each device will be of the form:
ifcfg-id-xx:xx:xx:xx:xx:xx
......@@ -459,7 +557,7 @@ the device's permanent MAC address.
Once the set of ifcfg-id-xx:xx:xx:xx:xx:xx files has been
created, it is necessary to edit the configuration files for the slave
devices (the MAC addresses correspond to those of the slave devices).
Before editing, the file will contain muliple lines, and will look
Before editing, the file will contain multiple lines, and will look
something like this:
BOOTPROTO='dhcp'
......@@ -496,16 +594,11 @@ STARTMODE="onboot"
BONDING_MASTER="yes"
BONDING_MODULE_OPTS="mode=active-backup miimon=100"
BONDING_SLAVE0="eth0"
BONDING_SLAVE1="eth1"
BONDING_SLAVE1="bus-pci-0000:06:08.1"
Replace the sample BROADCAST, IPADDR, NETMASK and NETWORK
values with the appropriate values for your network.
Note that configuring the bonding device with BOOTPROTO='dhcp'
does not work; the scripts attempt to obtain the device address from
DHCP prior to adding any of the slave devices. Without active slaves,
the DHCP requests are not sent to the network.
The STARTMODE specifies when the device is brought online.
The possible values are:
......@@ -531,9 +624,17 @@ for the bonding mode, link monitoring, and so on here. Do not include
the max_bonds bonding parameter; this will confuse the configuration
system if you have multiple bonding devices.
Finally, supply one BONDING_SLAVEn="ethX" for each slave,
where "n" is an increasing value, one for each slave, and "ethX" is
the name of the slave device (eth0, eth1, etc).
Finally, supply one BONDING_SLAVEn="slave device" for each
slave. where "n" is an increasing value, one for each slave. The
"slave device" is either an interface name, e.g., "eth0", or a device
specifier for the network device. The interface name is easier to
find, but the ethN names are subject to change at boot time if, e.g.,
a device early in the sequence has failed. The device specifiers
(bus-pci-0000:06:08.1 in the example above) specify the physical
network device, and will not change unless the device's bus location
changes (for example, it is moved from one PCI slot to another). The
example above uses one of each type for demonstration purposes; most
configurations will choose one or the other for all slave devices.
When all configuration files have been modified or created,
networking must be restarted for the configuration changes to take
......@@ -544,7 +645,7 @@ effect. This can be accomplished via the following:
Note that the network control script (/sbin/ifdown) will
remove the bonding module as part of the network shutdown processing,
so it is not necessary to remove the module by hand if, e.g., the
module paramters have changed.
module parameters have changed.
Also, at this writing, YaST/YaST2 will not manage bonding
devices (they do not show bonding interfaces on its list of network
......@@ -559,12 +660,37 @@ format can be found in an example ifcfg template file:
Note that the template does not document the various BONDING_
settings described above, but does describe many of the other options.
3.1.1 Using DHCP with sysconfig
-------------------------------
Under sysconfig, configuring a device with BOOTPROTO='dhcp'
will cause it to query DHCP for its IP address information. At this
writing, this does not function for bonding devices; the scripts
attempt to obtain the device address from DHCP prior to adding any of
the slave devices. Without active slaves, the DHCP requests are not
sent to the network.
3.1.2 Configuring Multiple Bonds with sysconfig
-----------------------------------------------
The sysconfig network initialization system is capable of
handling multiple bonding devices. All that is necessary is for each
bonding instance to have an appropriately configured ifcfg-bondX file
(as described above). Do not specify the "max_bonds" parameter to any
instance of bonding, as this will confuse sysconfig. If you require
multiple bonding devices with identical parameters, create multiple
ifcfg-bondX files.
Because the sysconfig scripts supply the bonding module
options in the ifcfg-bondX file, it is not necessary to add them to
the system /etc/modules.conf or /etc/modprobe.conf configuration file.
3.2 Configuration with initscripts support
------------------------------------------
This section applies to distros using a version of initscripts
with bonding support, for example, Red Hat Linux 9 or Red Hat
Enterprise Linux version 3. On these systems, the network
Enterprise Linux version 3 or 4. On these systems, the network
initialization scripts have some knowledge of bonding, and can be
configured to control bonding devices.
......@@ -614,10 +740,11 @@ USERCTL=no
Be sure to change the networking specific lines (IPADDR,
NETMASK, NETWORK and BROADCAST) to match your network configuration.
Finally, it is necessary to edit /etc/modules.conf to load the
bonding module when the bond0 interface is brought up. The following
sample lines in /etc/modules.conf will load the bonding module, and
select its options:
Finally, it is necessary to edit /etc/modules.conf (or
/etc/modprobe.conf, depending upon your distro) to load the bonding
module with your desired options when the bond0 interface is brought
up. The following lines in /etc/modules.conf (or modprobe.conf) will
load the bonding module, and select its options:
alias bond0 bonding
options bond0 mode=balance-alb miimon=100
......@@ -629,6 +756,33 @@ options for your configuration.
will restart the networking subsystem and your bond link should be now
up and running.
3.2.1 Using DHCP with initscripts
---------------------------------
Recent versions of initscripts (the version supplied with
Fedora Core 3 and Red Hat Enterprise Linux 4 is reported to work) do
have support for assigning IP information to bonding devices via DHCP.
To configure bonding for DHCP, configure it as described
above, except replace the line "BOOTPROTO=none" with "BOOTPROTO=dhcp"
and add a line consisting of "TYPE=Bonding". Note that the TYPE value
is case sensitive.
3.2.2 Configuring Multiple Bonds with initscripts
-------------------------------------------------
At this writing, the initscripts package does not directly
support loading the bonding driver multiple times, so the process for
doing so is the same as described in the "Configuring Multiple Bonds
Manually" section, below.
NOTE: It has been observed that some Red Hat supplied kernels
are apparently unable to rename modules at load time (the "-obonding1"
part). Attempts to pass that option to modprobe will produce an
"Operation not permitted" error. This has been reported on some
Fedora Core kernels, and has been seen on RHEL 4 as well. On kernels
exhibiting this problem, it will be impossible to configure multiple
bonds with differing parameters.
3.3 Configuring Bonding Manually
--------------------------------
......@@ -638,10 +792,11 @@ scripts (the sysconfig or initscripts package) do not have specific
knowledge of bonding. One such distro is SuSE Linux Enterprise Server
version 8.
The general methodology for these systems is to place the
bonding module parameters into /etc/modprobe.conf, then add modprobe
and/or ifenslave commands to the system's global init script. The
name of the global init script differs; for sysconfig, it is
The general method for these systems is to place the bonding
module parameters into /etc/modules.conf or /etc/modprobe.conf (as
appropriate for the installed distro), then add modprobe and/or
ifenslave commands to the system's global init script. The name of
the global init script differs; for sysconfig, it is
/etc/init.d/boot.local and for initscripts it is /etc/rc.d/rc.local.
For example, if you wanted to make a simple bond of two e100
......@@ -649,7 +804,7 @@ devices (presumed to be eth0 and eth1), and have it persist across
reboots, edit the appropriate file (/etc/init.d/boot.local or
/etc/rc.d/rc.local), and add the following:
modprobe bonding -obond0 mode=balance-alb miimon=100
modprobe bonding mode=balance-alb miimon=100
modprobe e100
ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up
ifenslave bond0 eth0
......@@ -657,11 +812,7 @@ ifenslave bond0 eth1
Replace the example bonding module parameters and bond0
network configuration (IP address, netmask, etc) with the appropriate
values for your configuration. The above example loads the bonding
module with the name "bond0," this simplifies the naming if multiple
bonding modules are loaded (each successive instance of the module is
given a different name, and the module instance names match the
bonding interface names).
values for your configuration.
Unfortunately, this method will not provide support for the
ifup and ifdown scripts on the bond devices. To reload the bonding
......@@ -684,20 +835,23 @@ appropriate device driver modules. For our example above, you can do
the following:
# ifconfig bond0 down
# rmmod bond0
# rmmod bonding
# rmmod e100
Again, for convenience, it may be desirable to create a script
with these commands.
3.4 Configuring Multiple Bonds
------------------------------
3.3.1 Configuring Multiple Bonds Manually
-----------------------------------------
This section contains information on configuring multiple
bonding devices with differing options. If you require multiple
bonding devices, but all with the same options, see the "max_bonds"
module paramter, documented above.
bonding devices with differing options for those systems whose network
initialization scripts lack support for configuring multiple bonds.
If you require multiple bonding devices, but all with the same
options, you may wish to use the "max_bonds" module parameter,
documented above.
To create multiple bonding devices with differing options, it
is necessary to load the bonding driver multiple times. Note that
......@@ -724,11 +878,16 @@ named "bond0" and creates the bond0 device in balance-rr mode with an
miimon of 100. The second instance is named "bond1" and creates the
bond1 device in balance-alb mode with an miimon of 50.
In some circumstances (typically with older distributions),
the above does not work, and the second bonding instance never sees
its options. In that case, the second options line can be substituted
as follows:
install bonding1 /sbin/modprobe bonding -obond1 mode=balance-alb miimon=50
This may be repeated any number of times, specifying a new and
unique name in place of bond0 or bond1 for each instance.
unique name in place of bond1 for each subsequent instance.
When the appropriate module paramters are in place, then
configure bonding according to the instructions for your distro.
5. Querying Bonding Configuration
=================================
......@@ -846,8 +1005,8 @@ tagged internally by bonding itself. As a result, bonding must
self generated packets.
For reasons of simplicity, and to support the use of adapters
that can do VLAN hardware acceleration offloding, the bonding
interface declares itself as fully hardware offloaing capable, it gets
that can do VLAN hardware acceleration offloading, the bonding
interface declares itself as fully hardware offloading capable, it gets
the add_vid/kill_vid notifications to gather the necessary
information, and it propagates those actions to the slaves. In case
of mixed adapter types, hardware accelerated tagged packets that
......@@ -880,7 +1039,7 @@ bond interface:
matches the hardware address of the VLAN interfaces.
Note that changing a VLAN interface's HW address would set the
underlying device -- i.e. the bonding interface -- to promiscouos
underlying device -- i.e. the bonding interface -- to promiscuous
mode, which might not be what you want.
......@@ -923,7 +1082,7 @@ down or have a problem making it unresponsive to ARP requests. Having
an additional target (or several) increases the reliability of the ARP
monitoring.
Multiple ARP targets must be seperated by commas as follows:
Multiple ARP targets must be separated by commas as follows:
# example options for ARP monitoring with three targets
alias bond0 bonding
......@@ -1045,7 +1204,7 @@ install bonding /sbin/modprobe tg3; /sbin/modprobe e1000;
This will, when loading the bonding module, rather than
performing the normal action, instead execute the provided command.
This command loads the device drivers in the order needed, then calls
modprobe with --ingore-install to cause the normal action to then take
modprobe with --ignore-install to cause the normal action to then take
place. Full documentation on this can be found in the modprobe.conf
and modprobe manual pages.
......@@ -1130,14 +1289,14 @@ association.
common to enable promiscuous mode on the device, so that all traffic
is seen (instead of seeing only traffic destined for the local host).
The bonding driver handles promiscuous mode changes to the bonding
master device (e.g., bond0), and propogates the setting to the slave
master device (e.g., bond0), and propagates the setting to the slave
devices.
For the balance-rr, balance-xor, broadcast, and 802.3ad modes,
the promiscuous mode setting is propogated to all slaves.
the promiscuous mode setting is propagated to all slaves.
For the active-backup, balance-tlb and balance-alb modes, the
promiscuous mode setting is propogated only to the active slave.
promiscuous mode setting is propagated only to the active slave.
For balance-tlb mode, the active slave is the slave currently
receiving inbound traffic.
......@@ -1148,46 +1307,182 @@ sending to peers that are unassigned or if the load is unbalanced.
For the active-backup, balance-tlb and balance-alb modes, when
the active slave changes (e.g., due to a link failure), the
promiscuous setting will be propogated to the new active slave.
promiscuous setting will be propagated to the new active slave.
12. High Availability Information
=================================
12. Configuring Bonding for High Availability
=============================================
High Availability refers to configurations that provide
maximum network availability by having redundant or backup devices,
links and switches between the host and the rest of the world.
There are currently two basic methods for configuring to
maximize availability. They are dependent on the network topology and
the primary goal of the configuration, but in general, a configuration
can be optimized for maximum available bandwidth, or for maximum
network availability.
links or switches between the host and the rest of the world. The
goal is to provide the maximum availability of network connectivity
(i.e., the network always works), even though other configurations
could provide higher throughput.
12.1 High Availability in a Single Switch Topology
--------------------------------------------------
If two hosts (or a host and a switch) are directly connected
via multiple physical links, then there is no network availability
penalty for optimizing for maximum bandwidth: there is only one switch
(or peer), so if it fails, you have no alternative access to fail over
to.
If two hosts (or a host and a single switch) are directly
connected via multiple physical links, then there is no availability
penalty to optimizing for maximum bandwidth. In this case, there is
only one switch (or peer), so if it fails, there is no alternative
access to fail over to. Additionally, the bonding load balance modes
support link monitoring of their members, so if individual links fail,
the load will be rebalanced across the remaining devices.
See Section 13, "Configuring Bonding for Maximum Throughput"
for information on configuring bonding with one peer device.
12.2 High Availability in a Multiple Switch Topology
----------------------------------------------------
With multiple switches, the configuration of bonding and the
network changes dramatically. In multiple switch topologies, there is
a trade off between network availability and usable bandwidth.
Below is a sample network, configured to maximize the
availability of the network:
| |
|port3 port3|
+-----+----+ +-----+----+
| |port2 ISL port2| |
| switch A +--------------------------+ switch B |
| | | |
+-----+----+ +-----++---+
|port1 port1|
| +-------+ |
+-------------+ host1 +---------------+
eth0 +-------+ eth1
In this configuration, there is a link between the two
switches (ISL, or inter switch link), and multiple ports connecting to
the outside world ("port3" on each switch). There is no technical
reason that this could not be extended to a third switch.
12.2.1 HA Bonding Mode Selection for Multiple Switch Topology
-------------------------------------------------------------
In a topology such as the example above, the active-backup and
broadcast modes are the only useful bonding modes when optimizing for
availability; the other modes require all links to terminate on the
same peer for them to behave rationally.
active-backup: This is generally the preferred mode, particularly if
the switches have an ISL and play together well. If the
network configuration is such that one switch is specifically
a backup switch (e.g., has lower capacity, higher cost, etc),
then the primary option can be used to insure that the
preferred link is always used when it is available.
broadcast: This mode is really a special purpose mode, and is suitable
only for very specific needs. For example, if the two
switches are not connected (no ISL), and the networks beyond
them are totally independent. In this case, if it is
necessary for some specific one-way traffic to reach both
independent networks, then the broadcast mode may be suitable.
12.2.2 HA Link Monitoring Selection for Multiple Switch Topology
----------------------------------------------------------------
The choice of link monitoring ultimately depends upon your
switch. If the switch can reliably fail ports in response to other
failures, then either the MII or ARP monitors should work. For
example, in the above example, if the "port3" link fails at the remote
end, the MII monitor has no direct means to detect this. The ARP
monitor could be configured with a target at the remote end of port3,
thus detecting that failure without switch support.
In general, however, in a multiple switch topology, the ARP
monitor can provide a higher level of reliability in detecting end to
end connectivity failures (which may be caused by the failure of any
individual component to pass traffic for any reason). Additionally,
the ARP monitor should be configured with multiple targets (at least
one for each switch in the network). This will insure that,
regardless of which switch is active, the ARP monitor has a suitable
target to query.
13. Configuring Bonding for Maximum Throughput
==============================================
13.1 Maximizing Throughput in a Single Switch Topology
------------------------------------------------------
In a single switch configuration, the best method to maximize
throughput depends upon the application and network environment. The
various load balancing modes each have strengths and weaknesses in
different environments, as detailed below.
For this discussion, we will break down the topologies into
two categories. Depending upon the destination of most traffic, we
categorize them into either "gatewayed" or "local" configurations.
In a gatewayed configuration, the "switch" is acting primarily
as a router, and the majority of traffic passes through this router to
other networks. An example would be the following:
Example 1 : host to switch (or other host)
+----------+ +----------+
| |eth0 eth0| switch |
| Host A +--------------------------+ or |
| +--------------------------+ other |
| |eth1 eth1| host |
| |eth0 port1| | to other networks
| Host A +---------------------+ router +------------------->
| +---------------------+ | Hosts B and C are out
| |eth1 port2| | here somewhere
+----------+ +----------+
The router may be a dedicated router device, or another host
acting as a gateway. For our discussion, the important point is that
the majority of traffic from Host A will pass through the router to
some other network before reaching its final destination.
12.1.1 Bonding Mode Selection for single switch topology
--------------------------------------------------------
In a gatewayed network configuration, although Host A may
communicate with many other systems, all of its traffic will be sent
and received via one other peer on the local network, the router.
Note that the case of two systems connected directly via
multiple physical links is, for purposes of configuring bonding, the
same as a gatewayed configuration. In that case, it happens that all
traffic is destined for the "gateway" itself, not some other network
beyond the gateway.
In a local configuration, the "switch" is acting primarily as
a switch, and the majority of traffic passes through this switch to
reach other stations on the same network. An example would be the
following:
+----------+ +----------+ +--------+
| |eth0 port1| +-------+ Host B |
| Host A +------------+ switch |port3 +--------+
| +------------+ | +--------+
| |eth1 port2| +------------------+ Host C |
+----------+ +----------+port4 +--------+
Again, the switch may be a dedicated switch device, or another
host acting as a gateway. For our discussion, the important point is
that the majority of traffic from Host A is destined for other hosts
on the same local network (Hosts B and C in the above example).
In summary, in a gatewayed configuration, traffic to and from
the bonded device will be to the same MAC level peer on the network
(the gateway itself, i.e., the router), regardless of its final
destination. In a local configuration, traffic flows directly to and
from the final destinations, thus, each destination (Host B, Host C)
will be addressed directly by their individual MAC addresses.
This distinction between a gatewayed and a local network
configuration is important because many of the load balancing modes
available use the MAC addresses of the local network source and
destination to make load balancing decisions. The behavior of each
mode is described below.
13.1.1 MT Bonding Mode Selection for Single Switch Topology
-----------------------------------------------------------
This configuration is the easiest to set up and to understand,
although you will have to decide which bonding mode best suits your
needs. The tradeoffs for each mode are detailed below:
needs. The trade offs for each mode are detailed below:
balance-rr: This mode is the only mode that will permit a single
TCP/IP connection to stripe traffic across multiple
......@@ -1206,6 +1501,23 @@ balance-rr: This mode is the only mode that will permit a single
interface's worth of throughput, even after adjusting
tcp_reordering.
Note that this out of order delivery occurs when both the
sending and receiving systems are utilizing a multiple
interface bond. Consider a configuration in which a
balance-rr bond feeds into a single higher capacity network
channel (e.g., multiple 100Mb/sec ethernets feeding a single
gigabit ethernet via an etherchannel capable switch). In this
configuration, traffic sent from the multiple 100Mb devices to
a destination connected to the gigabit device will not see
packets out of order. However, traffic sent from the gigabit
device to the multiple 100Mb devices may or may not see
traffic out of order, depending upon the balance policy of the
switch. Many switches do not support any modes that stripe
traffic (instead choosing a port based upon IP or MAC level
addresses); for those devices, traffic flowing from the
gigabit device to the many 100Mb devices will only utilize one
interface.
If you are utilizing protocols other than TCP/IP, UDP for
example, and your application can tolerate out of order
delivery, then this mode can allow for single stream datagram
......@@ -1220,16 +1532,21 @@ active-backup: There is not much advantage in this network topology to
connected to the same peer as the primary. In this case, a
load balancing mode (with link monitoring) will provide the
same level of network availability, but with increased
available bandwidth. On the plus side, it does not require
any configuration of the switch.
available bandwidth. On the plus side, active-backup mode
does not require any configuration of the switch, so it may
have value if the hardware available does not support any of
the load balance modes.
balance-xor: This mode will limit traffic such that packets destined
for specific peers will always be sent over the same
interface. Since the destination is determined by the MAC
addresses involved, this may be desirable if you have a large
network with many hosts. It is likely to be suboptimal if all
your traffic is passed through a single router, however. As
with balance-rr, the switch ports need to be configured for
addresses involved, this mode works best in a "local" network
configuration (as described above), with destinations all on
the same local network. This mode is likely to be suboptimal
if all your traffic is passed through a single router (i.e., a
"gatewayed" network configuration, as described above).
As with balance-rr, the switch ports need to be configured for
"etherchannel" or "trunking."
broadcast: Like active-backup, there is not much advantage to this
......@@ -1241,122 +1558,131 @@ broadcast: Like active-backup, there is not much advantage to this
protocol includes automatic configuration of the aggregates,
so minimal manual configuration of the switch is needed
(typically only to designate that some set of devices is
usable for 802.3ad). The 802.3ad standard also mandates that
frames be delivered in order (within certain limits), so in
general single connections will not see misordering of
available for 802.3ad). The 802.3ad standard also mandates
that frames be delivered in order (within certain limits), so
in general single connections will not see misordering of
packets. The 802.3ad mode does have some drawbacks: the
standard mandates that all devices in the aggregate operate at
the same speed and duplex. Also, as with all bonding load
balance modes other than balance-rr, no single connection will
be able to utilize more than a single interface's worth of
bandwidth. Additionally, the linux bonding 802.3ad
implementation distributes traffic by peer (using an XOR of
MAC addresses), so in general all traffic to a particular
destination will use the same interface. Finally, the 802.3ad
mode mandates the use of the MII monitor, therefore, the ARP
monitor is not available in this mode.
balance-tlb: This mode is also a good choice for this type of
topology. It has no special switch configuration
requirements, and balances outgoing traffic by peer, in a
vaguely intelligent manner (not a simple XOR as in balance-xor
or 802.3ad mode), so that unlucky MAC addresses will not all
"bunch up" on a single interface. Interfaces may be of
differing speeds. On the down side, in this mode all incoming
traffic arrives over a single interface, this mode requires
certain ethtool support in the network device driver of the
slave interfaces, and the ARP monitor is not available.
balance-alb: This mode is everything that balance-tlb is, and more. It
has all of the features (and restrictions) of balance-tlb, and
will also balance incoming traffic from peers (as described in
the Bonding Module Options section, above). The only extra
down side to this mode is that the network device driver must
support changing the hardware address while the device is
open.
12.1.2 Link Monitoring for Single Switch Topology
-------------------------------------------------
bandwidth.
Additionally, the linux bonding 802.3ad implementation
distributes traffic by peer (using an XOR of MAC addresses),
so in a "gatewayed" configuration, all outgoing traffic will
generally use the same device. Incoming traffic may also end
up on a single device, but that is dependent upon the
balancing policy of the peer's 8023.ad implementation. In a
"local" configuration, traffic will be distributed across the
devices in the bond.
Finally, the 802.3ad mode mandates the use of the MII monitor,
therefore, the ARP monitor is not available in this mode.
balance-tlb: The balance-tlb mode balances outgoing traffic by peer.
Since the balancing is done according to MAC address, in a
"gatewayed" configuration (as described above), this mode will
send all traffic across a single device. However, in a
"local" network configuration, this mode balances multiple
local network peers across devices in a vaguely intelligent
manner (not a simple XOR as in balance-xor or 802.3ad mode),
so that mathematically unlucky MAC addresses (i.e., ones that
XOR to the same value) will not all "bunch up" on a single
interface.
Unlike 802.3ad, interfaces may be of differing speeds, and no
special switch configuration is required. On the down side,
in this mode all incoming traffic arrives over a single
interface, this mode requires certain ethtool support in the
network device driver of the slave interfaces, and the ARP
monitor is not available.
balance-alb: This mode is everything that balance-tlb is, and more.
It has all of the features (and restrictions) of balance-tlb,
and will also balance incoming traffic from local network
peers (as described in the Bonding Module Options section,
above).
The only additional down side to this mode is that the network
device driver must support changing the hardware address while
the device is open.
13.1.2 MT Link Monitoring for Single Switch Topology
----------------------------------------------------
The choice of link monitoring may largely depend upon which
mode you choose to use. The more advanced load balancing modes do not
support the use of the ARP monitor, and are thus restricted to using
the MII monitor (which does not provide as high a level of assurance
as the ARP monitor).
12.2 High Availability in a Multiple Switch Topology
----------------------------------------------------
With multiple switches, the configuration of bonding and the
network changes dramatically. In multiple switch topologies, there is
a tradeoff between network availability and usable bandwidth.
Below is a sample network, configured to maximize the
availability of the network:
| |
|port3 port3|
+-----+----+ +-----+----+
| |port2 ISL port2| |
| switch A +--------------------------+ switch B |
| | | |
+-----+----+ +-----++---+
|port1 port1|
| +-------+ |
+-------------+ host1 +---------------+
eth0 +-------+ eth1
In this configuration, there is a link between the two
switches (ISL, or inter switch link), and multiple ports connecting to
the outside world ("port3" on each switch). There is no technical
reason that this could not be extended to a third switch.
12.2.1 Bonding Mode Selection for Multiple Switch Topology
----------------------------------------------------------
In a topology such as this, the active-backup and broadcast
modes are the only useful bonding modes; the other modes require all
links to terminate on the same peer for them to behave rationally.
active-backup: This is generally the preferred mode, particularly if
the switches have an ISL and play together well. If the
network configuration is such that one switch is specifically
a backup switch (e.g., has lower capacity, higher cost, etc),
then the primary option can be used to insure that the
preferred link is always used when it is available.
broadcast: This mode is really a special purpose mode, and is suitable
only for very specific needs. For example, if the two
switches are not connected (no ISL), and the networks beyond
them are totally independant. In this case, if it is
necessary for some specific one-way traffic to reach both
independent networks, then the broadcast mode may be suitable.
12.2.2 Link Monitoring Selection for Multiple Switch Topology
the MII monitor (which does not provide as high a level of end to end
assurance as the ARP monitor).
13.2 Maximum Throughput in a Multiple Switch Topology
-----------------------------------------------------
Multiple switches may be utilized to optimize for throughput
when they are configured in parallel as part of an isolated network
between two or more systems, for example:
+-----------+
| Host A |
+-+---+---+-+
| | |
+--------+ | +---------+
| | |
+------+---+ +-----+----+ +-----+----+
| Switch A | | Switch B | | Switch C |
+------+---+ +-----+----+ +-----+----+
| | |
+--------+ | +---------+
| | |
+-+---+---+-+
| Host B |
+-----------+
In this configuration, the switches are isolated from one
another. One reason to employ a topology such as this is for an
isolated network with many hosts (a cluster configured for high
performance, for example), using multiple smaller switches can be more
cost effective than a single larger switch, e.g., on a network with 24
hosts, three 24 port switches can be significantly less expensive than
a single 72 port switch.
If access beyond the network is required, an individual host
can be equipped with an additional network device connected to an
external network; this host then additionally acts as a gateway.
13.2.1 MT Bonding Mode Selection for Multiple Switch Topology
-------------------------------------------------------------
The choice of link monitoring ultimately depends upon your
switch. If the switch can reliably fail ports in response to other
failures, then either the MII or ARP monitors should work. For
example, in the above example, if the "port3" link fails at the remote
end, the MII monitor has no direct means to detect this. The ARP
monitor could be configured with a target at the remote end of port3,
thus detecting that failure without switch support.
In actual practice, the bonding mode typically employed in
configurations of this type is balance-rr. Historically, in this
network configuration, the usual caveats about out of order packet
delivery are mitigated by the use of network adapters that do not do
any kind of packet coalescing (via the use of NAPI, or because the
device itself does not generate interrupts until some number of
packets has arrived). When employed in this fashion, the balance-rr
mode allows individual connections between two hosts to effectively
utilize greater than one interface's bandwidth.
In general, however, in a multiple switch topology, the ARP
monitor can provide a higher level of reliability in detecting link
failures. Additionally, it should be configured with multiple targets
(at least one for each switch in the network). This will insure that,
regardless of which switch is active, the ARP monitor has a suitable
target to query.
13.2.2 MT Link Monitoring for Multiple Switch Topology
------------------------------------------------------
Again, in actual practice, the MII monitor is most often used
in this configuration, as performance is given preference over
availability. The ARP monitor will function in this topology, but its
advantages over the MII monitor are mitigated by the volume of probes
needed as the number of systems involved grows (remember that each
host in the network is configured with bonding).
12.3 Switch Behavior Issues for High Availability
-------------------------------------------------
14. Switch Behavior Issues
==========================
You may encounter issues with the timing of link up and down
reporting by the switch.
14.1 Link Establishment and Failover Delays
-------------------------------------------
Some switches exhibit undesirable behavior with regard to the
timing of link up and down reporting by the switch.
First, when a link comes up, some switches may indicate that
the link is up (carrier available), but not pass traffic over the
......@@ -1370,30 +1696,70 @@ relevant interface(s).
Second, some switches may "bounce" the link state one or more
times while a link is changing state. This occurs most commonly while
the switch is initializing. Again, an appropriate updelay value may
help, but note that if all links are down, then updelay is ignored
when any link becomes active (the slave closest to completing its
updelay is chosen).
help.
Note that when a bonding interface has no active links, the
driver will immediately reuse the first link that goes up, even if
updelay parameter was specified. If there are slave interfaces
waiting for the updelay timeout to expire, the interface that first
went into that state will be immediately reused. This reduces down
time of the network if the value of updelay has been overestimated.
driver will immediately reuse the first link that goes up, even if the
updelay parameter has been specified (the updelay is ignored in this
case). If there are slave interfaces waiting for the updelay timeout
to expire, the interface that first went into that state will be
immediately reused. This reduces down time of the network if the
value of updelay has been overestimated, and since this occurs only in
cases with no connectivity, there is no additional penalty for
ignoring the updelay.
In addition to the concerns about switch timings, if your
switches take a long time to go into backup mode, it may be desirable
to not activate a backup interface immediately after a link goes down.
Failover may be delayed via the downdelay bonding module option.
13. Hardware Specific Considerations
14.2 Duplicated Incoming Packets
--------------------------------
It is not uncommon to observe a short burst of duplicated
traffic when the bonding device is first used, or after it has been
idle for some period of time. This is most easily observed by issuing
a "ping" to some other host on the network, and noticing that the
output from ping flags duplicates (typically one per slave).
For example, on a bond in active-backup mode with five slaves
all connected to one switch, the output may appear as follows:
# ping -n 10.0.4.2
PING 10.0.4.2 (10.0.4.2) from 10.0.3.10 : 56(84) bytes of data.
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.7 ms
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=2 ttl=64 time=0.216 ms
64 bytes from 10.0.4.2: icmp_seq=3 ttl=64 time=0.267 ms
64 bytes from 10.0.4.2: icmp_seq=4 ttl=64 time=0.222 ms
This is not due to an error in the bonding driver, rather, it
is a side effect of how many switches update their MAC forwarding
tables. Initially, the switch does not associate the MAC address in
the packet with a particular switch port, and so it may send the
traffic to all ports until its MAC forwarding table is updated. Since
the interfaces attached to the bond may occupy multiple ports on a
single switch, when the switch (temporarily) floods the traffic to all
ports, the bond device receives multiple copies of the same packet
(one per slave device).
The duplicated packet behavior is switch dependent, some
switches exhibit this, and some do not. On switches that display this
behavior, it can be induced by clearing the MAC forwarding table (on
most Cisco switches, the privileged command "clear mac address-table
dynamic" will accomplish this).
15. Hardware Specific Considerations
====================================
This section contains additional information for configuring
bonding on specific hardware platforms, or for interfacing bonding
with particular switches or other devices.
13.1 IBM BladeCenter
15.1 IBM BladeCenter
--------------------
This applies to the JS20 and similar systems.
......@@ -1407,12 +1773,12 @@ JS20 network adapter information
--------------------------------
All JS20s come with two Broadcom Gigabit Ethernet ports
integrated on the planar. In the BladeCenter chassis, the eth0 port
of all JS20 blades is hard wired to I/O Module #1; similarly, all eth1
ports are wired to I/O Module #2. An add-on Broadcom daughter card
can be installed on a JS20 to provide two more Gigabit Ethernet ports.
These ports, eth2 and eth3, are wired to I/O Modules 3 and 4,
respectively.
integrated on the planar (that's "motherboard" in IBM-speak). In the
BladeCenter chassis, the eth0 port of all JS20 blades is hard wired to
I/O Module #1; similarly, all eth1 ports are wired to I/O Module #2.
An add-on Broadcom daughter card can be installed on a JS20 to provide
two more Gigabit Ethernet ports. These ports, eth2 and eth3, are
wired to I/O Modules 3 and 4, respectively.
Each I/O Module may contain either a switch or a passthrough
module (which allows ports to be directly connected to an external
......@@ -1432,29 +1798,30 @@ BladeCenter networking configuration
of ways, this discussion will be confined to describing basic
configurations.
Normally, Ethernet Switch Modules (ESM) are used in I/O
Normally, Ethernet Switch Modules (ESMs) are used in I/O
modules 1 and 2. In this configuration, the eth0 and eth1 ports of a
JS20 will be connected to different internal switches (in the
respective I/O modules).
An optical passthru module (OPM) connects the I/O module
directly to an external switch. By using OPMs in I/O module #1 and
#2, the eth0 and eth1 interfaces of a JS20 can be redirected to the
outside world and connected to a common external switch.
Depending upon the mix of ESM and OPM modules, the network
will appear to bonding as either a single switch topology (all OPM
modules) or as a multiple switch topology (one or more ESM modules,
zero or more OPM modules). It is also possible to connect ESM modules
together, resulting in a configuration much like the example in "High
Availability in a multiple switch topology."
Requirements for specifc modes
------------------------------
The balance-rr mode requires the use of OPM modules for
devices in the bond, all connected to an common external switch. That
switch must be configured for "etherchannel" or "trunking" on the
A passthrough module (OPM or CPM, optical or copper,
passthrough module) connects the I/O module directly to an external
switch. By using PMs in I/O module #1 and #2, the eth0 and eth1
interfaces of a JS20 can be redirected to the outside world and
connected to a common external switch.
Depending upon the mix of ESMs and PMs, the network will
appear to bonding as either a single switch topology (all PMs) or as a
multiple switch topology (one or more ESMs, zero or more PMs). It is
also possible to connect ESMs together, resulting in a configuration
much like the example in "High Availability in a Multiple Switch
Topology," above.
Requirements for specific modes
-------------------------------
The balance-rr mode requires the use of passthrough modules
for devices in the bond, all connected to an common external switch.
That switch must be configured for "etherchannel" or "trunking" on the
appropriate ports, as is usual for balance-rr.
The balance-alb and balance-tlb modes will function with
......@@ -1484,17 +1851,18 @@ connected to the JS20 system.
Other concerns
--------------
The Serial Over LAN link is established over the primary
The Serial Over LAN (SoL) link is established over the primary
ethernet (eth0) only, therefore, any loss of link to eth0 will result
in losing your SoL connection. It will not fail over with other
network traffic.
network traffic, as the SoL system is beyond the control of the
bonding driver.
It may be desirable to disable spanning tree on the switch
(either the internal Ethernet Switch Module, or an external switch) to
avoid fail-over delays issues when using bonding.
avoid fail-over delay issues when using bonding.
14. Frequently Asked Questions
16. Frequently Asked Questions
==============================
1. Is it SMP safe?
......@@ -1505,8 +1873,8 @@ The new driver was designed to be SMP safe from the start.
2. What type of cards will work with it?
Any Ethernet type cards (you can even mix cards - a Intel
EtherExpress PRO/100 and a 3com 3c905b, for example). They need not
be of the same speed.
EtherExpress PRO/100 and a 3com 3c905b, for example). For most modes,
devices need not be of the same speed.
3. How many bonding devices can I have?
......@@ -1524,11 +1892,12 @@ system.
disabled. The active-backup mode will fail over to a backup link, and
other modes will ignore the failed link. The link will continue to be
monitored, and should it recover, it will rejoin the bond (in whatever
manner is appropriate for the mode). See the section on High
Availability for additional information.
manner is appropriate for the mode). See the sections on High
Availability and the documentation for each mode for additional
information.
Link monitoring can be enabled via either the miimon or
arp_interval paramters (described in the module paramters section,
arp_interval parameters (described in the module parameters section,
above). In general, miimon monitors the carrier state as sensed by
the underlying network device, and the arp monitor (arp_interval)
monitors connectivity to another host on the local network.
......@@ -1536,7 +1905,7 @@ monitors connectivity to another host on the local network.
If no link monitoring is configured, the bonding driver will
be unable to detect link failures, and will assume that all links are
always available. This will likely result in lost packets, and a
resulting degredation of performance. The precise performance loss
resulting degradation of performance. The precise performance loss
depends upon the bonding mode and network configuration.
6. Can bonding be used for High Availability?
......@@ -1550,12 +1919,12 @@ depends upon the bonding mode and network configuration.
In the basic balance modes (balance-rr and balance-xor), it
works with any system that supports etherchannel (also called
trunking). Most managed switches currently available have such
support, and many unmananged switches as well.
support, and many unmanaged switches as well.
The advanced balance modes (balance-tlb and balance-alb) do
not have special switch requirements, but do need device drivers that
support specific features (described in the appropriate section under
module paramters, above).
module parameters, above).
In 802.3ad mode, it works with with systems that support IEEE
802.3ad Dynamic Link Aggregation. Most managed and many unmanaged
......@@ -1565,17 +1934,19 @@ switches currently available support 802.3ad.
8. Where does a bonding device get its MAC address from?
If not explicitly configured with ifconfig, the MAC address of
the bonding device is taken from its first slave device. This MAC
address is then passed to all following slaves and remains persistent
(even if the the first slave is removed) until the bonding device is
brought down or reconfigured.
If not explicitly configured (with ifconfig or ip link), the
MAC address of the bonding device is taken from its first slave
device. This MAC address is then passed to all following slaves and
remains persistent (even if the the first slave is removed) until the
bonding device is brought down or reconfigured.
If you wish to change the MAC address, you can set it with
ifconfig:
ifconfig or ip link:
# ifconfig bond0 hw ether 00:11:22:33:44:55
# ip link set bond0 address 66:77:88:99:aa:bb
The MAC address can be also changed by bringing down/up the
device and then changing its slaves (or their order):
......@@ -1591,23 +1962,28 @@ from the bond (`ifenslave -d bond0 eth0'). The bonding driver will
then restore the MAC addresses that the slaves had before they were
enslaved.
15. Resources and Links
16. Resources and Links
=======================
The latest version of the bonding driver can be found in the latest
version of the linux kernel, found on http://kernel.org
The latest version of this document can be found in either the latest
kernel source (named Documentation/networking/bonding.txt), or on the
bonding sourceforge site:
http://www.sourceforge.net/projects/bonding
Discussions regarding the bonding driver take place primarily on the
bonding-devel mailing list, hosted at sourceforge.net. If you have
questions or problems, post them to the list.
questions or problems, post them to the list. The list address is:
bonding-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bonding-devel
There is also a project site on sourceforge.
The administrative interface (to subscribe or unsubscribe) can
be found at:
http://www.sourceforge.net/projects/bonding
https://lists.sourceforge.net/lists/listinfo/bonding-devel
Donald Becker's Ethernet Drivers and diag programs may be found at :
- http://www.scyld.com/network/
......
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