I recently implemented Kopia to replace Duplicati on some systems in my network. Now that I have more than a week of backups, I have gained appreciation for the retention tags they use in the KopiaUI program.

It does a good job of indicating why this version is being retained while also showing how many copies it is maintaining at each retention level. Really handy.

I just noticed the pin to the right. That lets you pin the snapshot so it won't be removed during cleanup. That's kinda cool to be able to single one out to hang on a bit longer, maybe while investigating something I suspect went wrong after that snapshot.

I'm not shilling for Kopia, I haven't used it enough to be sure I trust it yet. I am hoping XO could blatantly steal this kind of idea for backups, especially delta backups. I often get confused about how to get the retention I want when configuring backups and when I search for answers I see other people are also confused.

I guess for the sake of completeness, this is how KopiaUI lets me configure retention:

Amazing timing. I have been having this issue with a VM I just set up and I came here to find out if this is a known problem, only to discover that the 97 patches I have been planning to install tonight are going to fix it.

Thank you @florent. I'll do that.

Update: It worked.

@Forza Sorry, you were correct, I just mixed in another new issue. NFS is currently used only for backups. All my SRs are in local storage. It just happened that I now have backups failing not just because of the NFS issue but because of the VDI issue but I think it's a side-effect of the NFS problem causing the backup to get interrupted so now the VDI is stuck attached to dom0. I should have made that more clear or never mentioned the VDI issue at all.

@Forza Seems you are correct about showmount. On UNRAID running v4 showmount says there are no clients connected. I previously assumed that meant XO only connected during the backup. When I look at /proc/fs/nfsd/clients I see the connections.

On Synology, running v3, showmount does show the XO IP connected. Synology is supposed to support v4 and I have the share set to allow v4 but XO had trouble connecting that way. Synology is pretty limited in what options it lets me set for NFS shares.

Synology doesn't have rcpdebug available. I'll see if I can figure out how to get more logging info about NFS.

@olivierlambert Well, last night the backup completed just fine despite me taking no action.

I updated the XO to the latest commit when I got in this morning so hopefully the issue I had back in June don't come back.

@julien-f Thank you, that's super helpful and even easier than I thought it would be.

@florent Yeah, it's a lot of data, thankfully my other VMs are not nearly as large. I'm still not sure why it failed when none of the virtual drives are 2TB. The largest ones are configured with a 1.82TB max so even the capacity of the drive is less than the max.

I'm moving ahead with a file level sync attempt to see if that works.

To be clear, this post was as much or more about helping you figure out what's wrong so other people don't have the same issue, than it is about making this import work for my VM. With the flood you are getting from VMware refugees, I figure I'm not the only person with large drives to import. In other words, if there's something I can do to help you figure out why it fails then I'm willing to help.

@gskger Yeah, looks like it would be too tight. Ouch, those T4s are an order of magnitude more expensive. I'm definitely not interested in going that route.

@paco Oh, that's great information, thank you. I'd much rather reset that flag instead of constantly adjusting the fans.

@nikade I did install the 97 XCP patches and that night the VM that was failing to backup was able to successfully backup. It had a 500GB secondary drive that was formatted but totally empty.

I had not yet patched my XO from source to the latest, it was maybe 24 commits behind. On Friday I updated it so I will find out on Monday if those backups continued to work but I assume they did.

Amazing timing. I have been having this issue with a VM I just set up and I came here to find out if this is a known problem, only to discover that the 97 patches I have been planning to install tonight are going to fix it.

@paco Oh, that's great information, thank you. I'd much rather reset that flag instead of constantly adjusting the fans.

I recently implemented Kopia to replace Duplicati on some systems in my network. Now that I have more than a week of backups, I have gained appreciation for the retention tags they use in the KopiaUI program.

It does a good job of indicating why this version is being retained while also showing how many copies it is maintaining at each retention level. Really handy.

I just noticed the pin to the right. That lets you pin the snapshot so it won't be removed during cleanup. That's kinda cool to be able to single one out to hang on a bit longer, maybe while investigating something I suspect went wrong after that snapshot.

I'm not shilling for Kopia, I haven't used it enough to be sure I trust it yet. I am hoping XO could blatantly steal this kind of idea for backups, especially delta backups. I often get confused about how to get the retention I want when configuring backups and when I search for answers I see other people are also confused.

I guess for the sake of completeness, this is how KopiaUI lets me configure retention:

@JamfoFL Thank you for the follow-up. Now I feel like I can install those patches. Bonus that it appears there are 23 patches now rather than the 22 I saw last week. Now I'm glad I waited, though I think the newest patch doesn't apply to my hardware anyway.

Thank you @florent. I'll do that.

Update: It worked.

Those 5 mirror backups continued to fail over the weekend.

The good news is that the normal delta backups succeeded over the weekend and didn't have any random failures I've been seeing.

I have a couple Delta backups that target the same remote. Yesterday I set up a Mirror backup between that remote and another remote. When I ran the Mirror backup yesterday, it was successful.

Today 7 of the VMs succeed in the backup but 5 of them fail with:
Missing vdi <guid> which is a base for a delta

Could this be caused by the fact that the target for the Mirror backup used to be a target for the Delta backup so it has files on it already. Do I need to purge the folder entirely? I thought maybe that would give it a head start and the reason I'm using the Mirror backup is because the Delta backup used to fail randomly on random VMs when backing up to both remotes.

How would I go about diagnosing this? I assume since the guid for the vdi is missing, it's going to be hard for me to find since I can't find something that's missing. Alternatively, maybe it's because it's currently a weird mix of old Delta backups and new Mirror backups and maybe over the next few days it will purge enough old stuff that it will start working cleanly.

Should I delete the entire remote target of the Mirror to get it started cleanly? Or, more likely, delete all backups on that Mirror for the 5 VMs that failed with this error.

@JamfoFL Any luck getting this to work? I've put off installing the patches because I don't want to lose my XO installs.

@olivierlambert I totally forgot about mirror backups, thanks for the reminder.

I see that a mirror will let me have different backup retention on the mirror target than I do on the mirror source. That's fantastic in my case because the mirror source has less storage space than the mirror target. Using rsync would have limited the backup retention on the Synology.

Now can you tell me how to recover the hours I spent figuring out I couldn't get it working to pull from the Synology side then the time to figure out how to schedule tasks in UNRAID and learn rsync and confirm it would do what I want it to do?