VDIs attached to control domain can't be forgotten because they are attached to the control domain
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I had backups fail earlier this week. After more than 24 hours they were still in the
started
state. I restarted the XO (from source) VM and the backups are listed asInterrupted
. I wasn't surprised by this. Since then two of my VMs fail the backup withVDI must be free or attached to exactly one VM
. I was also not terribly surprised by that.Looking at the health info I can see that the drives for those two VMs are listed under VDIs attached to Control Domain. Since those backups failed the other day I know it's safe to forget them. I click the forget button and they remain. I check the logs and the log says:
OPERATION_NOT_ALLOWED(VBD '<guid>' still attached to '<guid for id 0>')
SSH into the host and run
list_domains
and that's how I confirmed that the second guid is for id 0 which I assume is the control domain since I see it frequently referred to as dom0, right?That means I need to detach/forget it from dom0 but I can't because it's attached to dom0. At least that's what it feels like is happening.
I tried creating a snapshot for one of the VMs then deleting it to see if that would fix it. I had seen in another forum post that someone fixed it that way. Didn't work.
Must I reboot the host to fix this? This is my primary host and I don't have shared storage so that's kinda a pain. I'll do it if that'll fix my backups but I don't want to do that if there's another reasonable way to fix it without such extreme measures.
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@CodeMercenary Great question! Similar situation here. Sorry you didn't get a response.
What did you end up doing?
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Hi,
It's really hard to answer because it could be many things. Without digging, the easiest way is to reboot the Dom0. Sometimes, you can have a stuck process open on a volume (eg tapdisk). But the backup code is providing more and more fail-safe to avoid getting to that point, please be sure to have always the latest commit.
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@olivierlambert thanks, my comment wasnโt meant as a criticism. I appreciate all you share so freely in both software and in the forums! Just was wondering how another user got on.
I have benefitted immensely thanks to Xen on bare metal over the years and while some people push towards KVM, I found the import process to XCP-NG very smooth once I got python2 built on the Debian12 dom0s that have served so well.
rdiff-backup was a really solid backup method for us using LVM snapshots and iscsi, so itโs just taking some time to get used to the GUI and the new CLI - and that the CLI can help resolve things stuck in the GUI. Your forums and personal posts are gold.
Automated boot testing after a backup is fantastic.
Thanks for everything!
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Don't worry, happy to help and to make sure everything works great for everyone (which is a challenge knowing there's the same number of unique setup than users )
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last weeks i always get that problem. Only way to detach vdi from dom0 - reboot host(
xe vbd-unplug uuid=
didn't work at that case. -
@andrewperry Sorry for the delay in responding; I think you posted while I was on vacation. I ended up rebooting the host and have not had the problem return since. Uh oh, I hope I didn't just jinx myself.