From 6b29eb848f741742a0f393df40bbcc176520bf27 Mon Sep 17 00:00:00 2001 From: Osier Yang Date: Wed, 22 Jan 2014 22:39:42 +0800 Subject: [PATCH] storage: Add document for possible problem on volume detection For pool which relies on remote resources, such as a "iscsi" type pool, since how long it takes to export the corresponding devices to host's sysfs is really depended, it could depend on the network connection, it also could depend on the host's udev procedures. So it's likely that the volumes are not able to be detected during pool starting process, polling the sysfs doesn't work, since we don't know how much time is best for the polling, and even worse, the volumes could still be not detected or partly not detected even after the polling. So we end up with a documentation to prompt the fact, in virsh manual. And as a small improvement, let's explicitly say no LUNs found in the debug log in that case. --- src/storage/storage_backend_scsi.c | 5 +++++ tools/virsh.pod | 9 +++++++++ 2 files changed, 14 insertions(+) diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c index 6f86ffce59..08e13313ac 100644 --- a/src/storage/storage_backend_scsi.c +++ b/src/storage/storage_backend_scsi.c @@ -495,6 +495,7 @@ virStorageBackendSCSIFindLUs(virStoragePoolObjPtr pool, DIR *devicedir = NULL; struct dirent *lun_dirent = NULL; char devicepattern[64]; + bool found = false; VIR_DEBUG("Discovering LUs on host %u", scanhost); @@ -516,11 +517,15 @@ virStorageBackendSCSIFindLUs(virStoragePoolObjPtr pool, continue; } + found = true; VIR_DEBUG("Found LU '%s'", lun_dirent->d_name); processLU(pool, scanhost, bus, target, lun); } + if (!found) + VIR_DEBUG("No LU found for pool %s", pool->def->name); + closedir(devicedir); return retval; diff --git a/tools/virsh.pod b/tools/virsh.pod index 77f9383012..9e670dadfb 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -2650,6 +2650,15 @@ Refresh the list of volumes contained in I. Start the storage I, which is previously defined but inactive. +B: A storage pool that relies on remote resources such as an +"iscsi" or a (v)HBA backed "scsi" pool may need to be refreshed multiple +times in order to have all the volumes detected (see B). +This is because the corresponding volume devices may not be present in +the host's filesystem during the initial pool startup or the current +refresh attempt. The number of refresh retries is dependant upon the +network connection and the time the host takes to export the +corresponding devices. + =item B I Undefine the configuration for an inactive I. -- GitLab