Re: [libvirt-users] External snapshot issue
On Sat, Apr 22, 2017 at 11:26:17PM -0500, Leroy Tennison wrote:
I have used
virsh snapshot-create-as <VM name> <snapshot name> "<snapshot
description>" --diskspec
"vda,snapshot=external,file=/path/to/external-snapshot" --disk-only
--atomic
To avoid creating libvirt metadata for external snapshots, here you can
provide the option '--no-metadata' to `virsh snapshot-create-as` so that
libvirt won't track the metadata anymore. This avoids having to delete
it manually (which you can do as I outlined further down below).
to create an external snapshot of a running VM. I followed it with
virsh blockpull <VM name> --path /path/to/external-snapshot
Slightly related: `blockcommit` is relatively faster than `blockpull` in
this case -- because your base image ("original-image-file.qcow") should
have the bulk of the content, so `blockcommit` will copy only the
_delta_ from the original, which was stored in your
'external-snapshot.qcow2', so it'll be a shorter copy operation.
Here's some notes related to it:
http://wiki.libvirt.org/page/Live-disk-backup-with-active-blockcommit
and monitored it until done. I confirmed it with
qemu-img info /path/to/external-snapshot
which shows no backing store.
However, when I do
grep {/etc,/run}/libvirt/qemu/<VM name>.xml
the xml for the VM still shows a backing store in the /run/... definition
(but not in the /etc/... definition, my understanding is that the /etc/...
definition won't be updated until the VM is shut down):
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2'/>
<source file='/var/lib/libvirt/images/external-snapshot.qcow2'/>
<backingStore type='file' index='1'>
<format type='qcow2'/>
<source
file='/var/lib/libvirt/images/original-image-file.qcow'/>
<backingStore/>
</backingStore>
<target dev='hda' bus='ide'/>
<alias name='ide0-0-0'/>
<address type='drive' controller='0' bus='0'
target='0' unit='0'/>
</disk>
This is using libvirtd version 1.3.1 and qemu-img version 2.5.0.
How do I resolve this situation? I don't want to have to rely on a backing
store permanently. Thanks for any help or pointers.
You can look at the existing snapshot metadata libvirt is tracking:
$ virsh snapshot-list --tree vm1
And then delete the metadata (the below command does that) for a named
snapshot:
$ virsh snapshot-delete vm1 --metadata snap1
--
/kashyap