libvirt users - Aug 2015 - virsh create snapshot not honoring diskspec?

Hi,
I'm trying to create a snapshot on a specific disk by using diskspec
option. However, libvirt/virsh seems to ignore it and takes a snapshot of
all disks. Am I using this option incorrectly?

In below examples, I'm trying to snapshot only vdb. However even vda is
getting snapshotted regardless of diskspec. Is this a known issue?

I'm on CentOS 7.1, libvirtd (libvirt) 1.2.8, virsh 1.2.8

[root@localhost scripts]# virsh domblklist centos_nfs
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-081800
vdb        /var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-081800
hdc        -

[root@localhost scripts]# virsh snapshot-create-as --domain centos_nfs
--name SNAP_2015-08-07-090909 --no-metadata --disk-only --atomic --diskspec
vdb,snapshot=external
Domain snapshot SNAP_2015-08-07-090909 created

[root@localhost scripts]# virsh domblklist centos_nfs
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-090909
vdb        /var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-090909
hdc        -


[root@localhost scripts]# virsh snapshot-create-as --domain centos_nfs
--name SNAP_2015-08-07-101010 --no-metadata --disk-only --atomic --diskspec
vdb,snapshot=external,file=/var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-101010
Domain snapshot SNAP_2015-08-07-101010 created

[root@localhost scripts]# virsh domblklist centos_nfs
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-101010
vdb        /var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-101010
hdc        -

Thanks,
KiranK

Checking in if anyone has thoughts on this?
Thanks,
KiranK

On Fri, Aug 7, 2015 at 8:53 AM, Silver Sky Soft Services, Inc. <
contactus@silverskysoft.com> wrote:
> Hi,
> I'm trying to create a snapshot on a specific disk by using diskspec
> option. However, libvirt/virsh seems to ignore it and takes a snapshot of
> all disks. Am I using this option incorrectly?
>
> In below examples, I'm trying to snapshot only vdb. However even vda is
> getting snapshotted regardless of diskspec. Is this a known issue?
>
> I'm on CentOS 7.1, libvirtd (libvirt) 1.2.8, virsh 1.2.8
>
> [root@localhost scripts]# virsh domblklist centos_nfs
> Target     Source
> ------------------------------------------------
> vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-081800
> vdb
>  /var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-081800
> hdc        -
>
> [root@localhost scripts]# virsh snapshot-create-as --domain centos_nfs
> --name SNAP_2015-08-07-090909 --no-metadata --disk-only --atomic --diskspec
> vdb,snapshot=external
> Domain snapshot SNAP_2015-08-07-090909 created
>
> [root@localhost scripts]# virsh domblklist centos_nfs
> Target     Source
> ------------------------------------------------
> vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-090909
> vdb
>  /var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-090909
> hdc        -
>
>
> [root@localhost scripts]# virsh snapshot-create-as --domain centos_nfs
> --name SNAP_2015-08-07-101010 --no-metadata --disk-only --atomic --diskspec
>
vdb,snapshot=external,file=/var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-101010
> Domain snapshot SNAP_2015-08-07-101010 created
>
> [root@localhost scripts]# virsh domblklist centos_nfs
> Target     Source
> ------------------------------------------------
> vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-101010
> vdb
>  /var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-101010
> hdc        -
>
> Thanks,
> KiranK
>

On 08/07/2015 09:53 AM, Silver Sky Soft Services, Inc.
wrote:
> Hi,
> I'm trying to create a snapshot on a specific disk by using diskspec
> option. However, libvirt/virsh seems to ignore it and takes a snapshot of
> all disks. Am I using this option incorrectly?
> 
> In below examples, I'm trying to snapshot only vdb. However even vda is
> getting snapshotted regardless of diskspec. Is this a known issue?
> 
> I'm on CentOS 7.1, libvirtd (libvirt) 1.2.8, virsh 1.2.8
> 
> [root@localhost scripts]# virsh domblklist centos_nfs
> Target     Source
> ------------------------------------------------
> vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-081800
> vdb       
/var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-081800
> hdc        -
> 
> [root@localhost scripts]# virsh snapshot-create-as --domain centos_nfs
> --name SNAP_2015-08-07-090909 --no-metadata --disk-only --atomic --diskspec
> vdb,snapshot=external
This command line did not give a diskspec for vda, so the action for vda
defaults to whatever the <domain> XML says is default for that disk .

Try giving:
 --diskspec vdb,snapshot=external --diskspec vda,snapshot=none
to explicitly override the <domain> defaults for both disks at once.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

On Thu, Aug 13, 2015 at 1:16 PM, Eric Blake <eblake@redhat.com>
wrote:
>
> On 08/07/2015 09:53 AM, Silver Sky Soft Services, Inc. wrote:
> > Hi,
> > I'm trying to create a snapshot on a specific disk by using
diskspec
> > option. However, libvirt/virsh seems to ignore it and takes a snapshot
of
> > all disks. Am I using this option incorrectly?
> >
> > In below examples, I'm trying to snapshot only vdb. However even
vda is
> > getting snapshotted regardless of diskspec. Is this a known issue?
> >
> > I'm on CentOS 7.1, libvirtd (libvirt) 1.2.8, virsh 1.2.8
> >
> > [root@localhost scripts]# virsh domblklist centos_nfs
> > Target     Source
> > ------------------------------------------------
> > vda        /var/lib/libvirt/images/centos_nfs.SNAP_2015-08-07-081800
> > vdb       
/var/lib/libvirt/images/centos_nfs_storage.SNAP_2015-08-07-081800
> > hdc        -
> >
> > [root@localhost scripts]# virsh snapshot-create-as --domain centos_nfs
> > --name SNAP_2015-08-07-090909 --no-metadata --disk-only --atomic
--diskspec
> > vdb,snapshot=external
>
> This command line did not give a diskspec for vda, so the action for vda
> defaults to whatever the <domain> XML says is default for that disk .
>
> Try giving:
>  --diskspec vdb,snapshot=external --diskspec vda,snapshot=none
> to explicitly override the <domain> defaults for both disks at once.
>
Thanks Eric. That helped. Although minor note was the option was
"snapshot=no" instead of "snapshot=none". Just to put in
these
archives, the working command:
virsh snapshot-create-as --domain cento_os --name snap3 --no-metadata
--disk-only --atomic --diskspec vdb,snapshot=no --diskspec
vda,snapshot=external

-KiranK