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:

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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.

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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

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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.

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Thanks for your inputs in advance.

Hakan Duran

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