
Hello, i cannot get sparsifying to work in lastest oVirt 4.5.4 release (not that i have tried with a previous release) I have two Data domains connected to oVirt using iSCSI & NFS. I created 2 testvm's and 50GB thin provisioned qcow2 disks for each, made some temp files, remove them and tried to sparsify, but it does not work. Error i am getting is: Error while executing action: Cannot sparsify Virtual Disk. Sparsifying is not supported for QCOW2 disk testvm1_Disk1. In virtual disk options i have enable, Bootable, incremental back and for one of the images i enable discard for testing purposes. What am i doing wrong?

Is it also broken on the NFS data domain, or only on iSCSI? As I understand, sparsifying isn't supported on iSCSI data domains. I am not sure of the reason why iSCSI domains don't support sparsify, but it would be great. I'd love an input from oVirt storage gurus to understand the limitation Guillaume Pavese Ingénieur Système et Réseau Interactiv-Group On Wed, Jan 11, 2023 at 11:35 PM <andreas_nikiforou@hotmail.com> wrote:
Hello,
i cannot get sparsifying to work in lastest oVirt 4.5.4 release (not that i have tried with a previous release)
I have two Data domains connected to oVirt using iSCSI & NFS.
I created 2 testvm's and 50GB thin provisioned qcow2 disks for each, made some temp files, remove them and tried to sparsify, but it does not work.
Error i am getting is: Error while executing action: Cannot sparsify Virtual Disk. Sparsifying is not supported for QCOW2 disk testvm1_Disk1.
In virtual disk options i have enable, Bootable, incremental back and for one of the images i enable discard for testing purposes.
What am i doing wrong? _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-leave@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/LBPY4DYC6TWYFK...
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Unfortunately yes, even VM's/disks on the NFS data domain are giving the same error. Just to be sure, i just created a completely new NFS data share on Truenas imported the data domain to ovirt and created a new test vm with 2 thin provisioned disks on it, cannot sparsify neither: "Error while executing action: Cannot sparsify Virtual Disk. Sparsifying is not supported for QCOW2 disk testvm3_Disk1." I checked the NFS share on Truenas to make sure i have a sparse qcow2 file and it is: -rw-rw---- 1 vdsm ovirt-kvm 24G Jan 12 12:57 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b -rw-rw---- 1 vdsm ovirt-kvm 1.0M Jan 12 12:44 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b.lease -rw-r--r-- 1 vdsm ovirt-kvm 307 Jan 12 12:44 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b.meta root@truenas[.../29dcdef7-8d1d-48bc-b9cf-3850102ec251]# file a0f82c8b-d2aa-442b-b28b-b25ca684dd7b a0f82c8b-d2aa-442b-b28b-b25ca684dd7b: QEMU QCOW2 Image (v3), 26843545600 bytes

ovirt-engine intentionally blocks sparsifying QCOW images since 4.4.4 because it confused users that didn't see the right amount of free space afterwards, see the following bug for more details: https://bugzilla.redhat.com/show_bug.cgi?id=1792905 On Thu, Jan 12, 2023 at 3:03 PM <andreas_nikiforou@hotmail.com> wrote:
Unfortunately yes, even VM's/disks on the NFS data domain are giving the same error.
Just to be sure, i just created a completely new NFS data share on Truenas imported the data domain to ovirt and created a new test vm with 2 thin provisioned disks on it, cannot sparsify neither:
"Error while executing action: Cannot sparsify Virtual Disk. Sparsifying is not supported for QCOW2 disk testvm3_Disk1."
I checked the NFS share on Truenas to make sure i have a sparse qcow2 file and it is:
-rw-rw---- 1 vdsm ovirt-kvm 24G Jan 12 12:57 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b -rw-rw---- 1 vdsm ovirt-kvm 1.0M Jan 12 12:44 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b.lease -rw-r--r-- 1 vdsm ovirt-kvm 307 Jan 12 12:44 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b.meta root@truenas[.../29dcdef7-8d1d-48bc-b9cf-3850102ec251]# file a0f82c8b-d2aa-442b-b28b-b25ca684dd7b a0f82c8b-d2aa-442b-b28b-b25ca684dd7b: QEMU QCOW2 Image (v3), 26843545600 bytes _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-leave@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/WT5I4O6BOXIOK2...

On Thu, Jan 12, 2023 at 3:15 PM Arik Hadas <ahadas@redhat.com> wrote:
ovirt-engine intentionally blocks sparsifying QCOW images since 4.4.4 because it confused users that didn't see the right amount of free space afterwards, see the following bug for more details: https://bugzilla.redhat.com/show_bug.cgi?id=1792905
Sorry, what I wrote above is incorrect - the space was indeed reclaimed and so the free space was correct but the image size didn't change (so if you don't care about the size of the image that you see in oVirt and you need to free space, it's fine to invoke it manually)
On Thu, Jan 12, 2023 at 3:03 PM <andreas_nikiforou@hotmail.com> wrote:
Unfortunately yes, even VM's/disks on the NFS data domain are giving the same error.
Just to be sure, i just created a completely new NFS data share on Truenas imported the data domain to ovirt and created a new test vm with 2 thin provisioned disks on it, cannot sparsify neither:
"Error while executing action: Cannot sparsify Virtual Disk. Sparsifying is not supported for QCOW2 disk testvm3_Disk1."
I checked the NFS share on Truenas to make sure i have a sparse qcow2 file and it is:
-rw-rw---- 1 vdsm ovirt-kvm 24G Jan 12 12:57 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b -rw-rw---- 1 vdsm ovirt-kvm 1.0M Jan 12 12:44 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b.lease -rw-r--r-- 1 vdsm ovirt-kvm 307 Jan 12 12:44 a0f82c8b-d2aa-442b-b28b-b25ca684dd7b.meta root@truenas[.../29dcdef7-8d1d-48bc-b9cf-3850102ec251]# file a0f82c8b-d2aa-442b-b28b-b25ca684dd7b a0f82c8b-d2aa-442b-b28b-b25ca684dd7b: QEMU QCOW2 Image (v3), 26843545600 bytes _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-leave@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/WT5I4O6BOXIOK2...

I see, weird that i couldn't find that bug report with google, even after spending so much time searching info on this topic. So what is the preferred method of freeing up space now, since sparsifying is disabled? Does enabling "discard" for VM disk take care of freeing up used space taken by deleted files on a thin provisioned disk? I have it enabled on few of my testvms but have not seen it have any effect, need to read up on that feature, only used sparsify previously for this operation.

On Thu, Jan 12, 2023 at 7:59 PM <andreas_nikiforou@hotmail.com> wrote:
I see, weird that i couldn't find that bug report with google, even after spending so much time searching info on this topic.
So what is the preferred method of freeing up space now, since sparsifying is disabled?
Sparsify-image is not disabled, it can still be invoked on raw volumes.
Does enabling "discard" for VM disk take care of freeing up used space taken by deleted files on a thin provisioned disk? I have it enabled on few of my testvms but have not seen it have any effect, need to read up on that feature, only used sparsify previously for this operation.
Yeah, pass-discard could be an option if your underlying storage supports it. You can read more about it in the original feature page: https://www.ovirt.org/develop/release-management/features/storage/pass-disca... But as I previously wrote, sparsifying the image without going through ovirt-engine (but let's say, with the VDSM API) is also an option if you don't care about the reduction in size not being reflect in oVirt
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participants (3)
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andreas_nikiforou@hotmail.com
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Arik Hadas
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Guillaume Pavese