QMP command 'system_reset' is issued after creating files in the guest. The
command has an effect similar to the physical reset button on a PC. But
filesystems may be left in an unclean state which causes the loss of data. Run
the command "sync" to flush the data to disk.
Signed-off-by: NPing Li <pingl@redhat.com>

This test allows to check all snapshots, but currently only checks the
main image and last snapshot. Let's check one of the middle snapshots as
well to see it behaves correctly.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The "drop_caches" should only be performed when we need to measure the
disk performance, which is not the case of live_snapshot_chain. Linux
kernel should make sure it uses the files it's suppose to be using and
caching is useful feature used out there in production.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

Signed-off-by: NQianqian Zhu <qizhu@redhat.com>

block job test will eat a lots of caches in testing,
free caches  after test to avoid VM hang memory.
Signed-off-by: NXu Tian <xutian@redhat.com>

Signed-off-by: NCong Li <coli@redhat.com>

1. Add snapshots to 64 for scalability test.
2. Verify sn64 works fine.
3. Add step "system_reset" after snapshot creation finish.
Signed-off-by: NCong Li <coli@redhat.com>

Use apt-get instead of yum for command.
Signed-off-by: NChris J Arges <chris.j.arges@canonical.com>

use "no raw qed vmdk" instead "only qcow2" because new image format (eg. qcow3)
maybe support in futuer;
Signed-off-by: NXu Tian <xutian@redhat.com>

Add five live snapshot cases have similar process:
- create live snapshot when guest paused
- restore to previous state when guest become crash
- restore live snapshot after guest update
- restore live snapshot chain 2-restore to base
- restore to parent snapshot node
Signed-off-by: NYiqiao Pu <ypu@redhat.com>

Update interface to date
Signed-off-by: NYiqiao Pu <ypu@redhat.com>
Signed-off-by: NFeng Yang <fyang@redhat.com>