Public bug reported:
virsh snapshot-create domainname snapfile.xml,
also
virsh snapshot-remove domainname snapshotname
needs reel time more then 30min.
Some Details.
The Guest is a qemu/kvm guest with Windows2008R2, and Virtio-drivern on
a 50GByte qcow2 Image, with cache=writeback and 4 virtual CPUs and
6GByte Memory
The Host is a i7-920 with 24GByte Memory, the Disk where the qcow2
image resides is local with software raid1 and a lvm Partition
I get native 100MByte/s to and from the harddisc through lvm and
software raid
I understand the a snapshot in qcow2-file wirtes flushes the disccache, writes
a file, writes the xml-description and writes the mainmemory and pause the
machine in this time. the resulting rate of writing the mainmemory is 6GB/30min
3,3MB/s
I thought a snapshot in shut off state, should not write the mainmemory of the
guest in the snapshot, because there is no valid mainmemory, but i think that
assumption failed - the time of snapshot in running / shut off state is always
the same.
the work-around perhaps can be the usage of the option --disk-only in
the shut off state, but i didn't understand why the normal snapshot
needs so long. At my assumption it would consume 2min real time max.
one detail i have seen, is that the guest sometimes ignores the shut-
down command. Perhaps the APC in the windows server is the cause of it,
that pause/suspend state isn't reached, and the command is repeated
until the snapshot can really perform.
** Affects: libvirt (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1131097
Title:
virsh snapshot-create is very slow independend of domain state
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