Dear all, Please let me start by indicating that I am not from a technical background, so please be gentle and patient with me. I am trying to get a snapshot from my virtual machines (vm) and the following command works for all of them bar one: # virsh snapshot-create-as --quiesce --no-metadata --domain myvm myvm-state --diskspec vda,file=overlay.qcow2 --disk-only --atomic The only exception is this one vm, which has two disks as two separete qcow2 files: vda and vdb. Vdb contains my nexcloud data, resides on a btrfs subvolume, and a daily snapshot of this subvolume is taken by a cronjob by the host machine. Therefore, I do not want to include it in the snapshot taken by virsh, and therefore I did not include vdb as a separate --diskspec item, and used the same command indicated above. However, this fails with the following behavior: a state (or rather overlay file with a qcow2 extension is created on the host machine's directory where the image of vdb exists. My question is the following: Is there a way to direct virsh for only taking a snapshot ignoring one of the disks? Yes, I can always create that second snapshot/overlay image of vdb and delete it later, but it doesn't feel very intuitive, and efficient. However, it is quite possible that I may be completely overseeing an important aspect of the process, and this may not be possible due to that :). Thanks for your inputs in advance. Hakan Duran
On Sun, Jan 05, 2020 at 17:21:52 -0600, Eyüp Hakan Duran wrote:> Dear all, > Please let me start by indicating that I am not from a technical > background, so please be gentle and patient with me. > > I am trying to get a snapshot from my virtual machines (vm) and the > following > command works for all of them bar one: > > # virsh snapshot-create-as --quiesce --no-metadata --domain myvm myvm-state > --diskspec vda,file=overlay.qcow2 --disk-only --atomicYou can drop --atomic if you use a qemu released in at least last 5 years as the snapshot is always atomic if the qemu supports the 'transaction' command.> > The only exception is this one vm, which has two disks as two separete > qcow2 files: vda and vdb. Vdb contains my nexcloud data, resides on a > btrfs subvolume, and a daily snapshot of this subvolume is taken by a > cronjob > by the host machine. Therefore, I do not want to include it in the > snapshot taken by virsh, and therefore I did not include vdb as a > separate --diskspec item, and used the same command indicated above. > However, this fails with the following behavior: a state (or rather > overlay file with a qcow2 extension is created on the host machine's > directory where the image of vdb exists. My question is the following: > Is there a way to direct virsh for only taking a snapshot ignoring one > of the disks? Yes, I can always create that second snapshot/overlaySure. Just use a second --diskspec vdb,snapshot=no> image of vdb and delete it later, but it doesn't feel very intuitive, > and efficient. However, it is quite possible that I may be completely > overseeing an important aspect of the process, and this may not be possible > due to that :).One disadvantage of the above operation is that the snapshot of vdb is not from the same time as vda, but if that doesn't pose a problem in your scenario it's okay to do it that way.> > Thanks for your inputs in advance. > > Hakan Duran> _______________________________________________ > libvirt-users mailing list > libvirt-users@redhat.com > https://www.redhat.com/mailman/listinfo/libvirt-users
Thank you so much for your informative response. The man page of virsh did not include "snapshot=no" sub-option under the --diskspec option, but it is very intuitive. Thanks developers for their excellent work! Hakan Peter Krempa <pkrempa@redhat.com>, 6 Oca 2020 Pzt, 02:57 tarihinde şunu yazdı:> On Sun, Jan 05, 2020 at 17:21:52 -0600, Eyüp Hakan Duran wrote: > > Dear all, > > Please let me start by indicating that I am not from a technical > > background, so please be gentle and patient with me. > > > > I am trying to get a snapshot from my virtual machines (vm) and the > > following > > command works for all of them bar one: > > > > # virsh snapshot-create-as --quiesce --no-metadata --domain myvm > myvm-state > > --diskspec vda,file=overlay.qcow2 --disk-only --atomic > > You can drop --atomic if you use a qemu released in at least last 5 > years as the snapshot is always atomic if the qemu supports the > 'transaction' command. > > > > > The only exception is this one vm, which has two disks as two separete > > qcow2 files: vda and vdb. Vdb contains my nexcloud data, resides on a > > btrfs subvolume, and a daily snapshot of this subvolume is taken by a > > cronjob > > by the host machine. Therefore, I do not want to include it in the > > snapshot taken by virsh, and therefore I did not include vdb as a > > separate --diskspec item, and used the same command indicated above. > > However, this fails with the following behavior: a state (or rather > > overlay file with a qcow2 extension is created on the host machine's > > directory where the image of vdb exists. My question is the following: > > Is there a way to direct virsh for only taking a snapshot ignoring one > > of the disks? Yes, I can always create that second snapshot/overlay > > Sure. Just use a second --diskspec vdb,snapshot=no > > > image of vdb and delete it later, but it doesn't feel very intuitive, > > and efficient. However, it is quite possible that I may be completely > > overseeing an important aspect of the process, and this may not be > possible > > due to that :). > > One disadvantage of the above operation is that the snapshot of vdb is > not from the same time as vda, but if that doesn't pose a problem in > your scenario it's okay to do it that way. > > > > > Thanks for your inputs in advance. > > > > Hakan Duran > > > _______________________________________________ > > libvirt-users mailing list > > libvirt-users@redhat.com > > https://www.redhat.com/mailman/listinfo/libvirt-users > >
On Mon, Jan 06, 2020 at 11:47:38 -0600, Eyüp Hakan Duran wrote:> Thank you so much for your informative response. The man page of virsh did > not include "snapshot=no" sub-option under the --diskspec option, but it is > very intuitive. Thanks developers for their excellent work!I propsed a fix to the man page: https://www.redhat.com/archives/libvir-list/2020-January/msg00204.html