Running PBS as a VM

[iprigger]

Hi All,

Just in case someone else wants to try something stupid: If you're running PBS as a VM, DO NOT try to backup your own PBS Server to PBS. Tried it - ended up with a broken backup (and pvestatd needing a restart).

Was it a stupid idea? Ummmm... somewhat ;-)

Otherwise... works brilliant!

Tobias

 

[t.lamprecht]

Haha, you could call it stupid but you could also call it brave and curious

If you want to backup the OS + configs, at least put the datastore on a second disk where you set "backup=false"

 

[iprigger]

Hi Thomas,

This is Jackass and we're doing Backups!

Haha, you could call it stupid but you could also call it brave and curious

If you want to backup the OS + configs, at least put the datastore on a second disk where you set "backup=false"

As always: Curiosity kills the cat

Easier way: Backup PBS using vzback to a different directory - and then do the backups using PBS with the exclude flag.

The error is not non-recoverable - so after restarting pvestatd everything is back to normal.

The nice thing about proxmox really is that it's not overly complicated and you have very, very few situations that really require you to actually reboot the cluster.

I normally do all 2-3 months once (and then move the VMs from one node to another and back).

Stability has always been very, very good with PVE.

Normally I don't think I have to do all mistakes by myself (I'm probably not going to live long enough) but try to learn something from other peoples mistakes. Now, someone else can save 15 minutes NOT doing my mistake. Fair enough

Tobias

 

[iprigger]

Hi again,

... on a completely different note: It would be very cool if we could somehow download the backup server configuration into an archive to store i.e. on a USB key or likewise.

This would simplify mitigating a backup server crash a lot!

Tobias

 

[iprigger]

Hi Thomas (again),

Just checked your Input about "different store with no backup"... I don't think this has anything to do with that.

I think the problem occurs here:
INFO: issuing guest-agent 'fs-freeze' command
INFO: issuing guest-agent 'fs-thaw' command

This seems to block the writes to the VM - and is generating some sort of inception - I see no way how this can be prevented...

FYI: I have my backup-data-store on an NFS share...

Tobias

 

[msproact]

Hmmm, I think it should only freeze local filesystems, no NFS exports:

Command: guest-fsfreeze-freeze
Sync and freeze all freezable, local guest filesystems. If this command succeeded, you may call guest-fsfreeze-thaw later to unfreeze.

QEMU Guest Agent Protocol Reference

However, PBS itself may use some temporary local filesystem directory.

 

[iprigger]

hi,

Hmmm, I think it should only freeze local filesystems, no NFS exports:

Command: guest-fsfreeze-freeze
Sync and freeze all freezable, local guest filesystems. If this command succeeded, you may call guest-fsfreeze-thaw later to unfreeze.

QEMU Guest Agent Protocol Reference

However, PBS itself may use some temporary local filesystem directory.

True. But the Proxmox Server runs on the local partition - and some stuff is most probably not going directly to the nfs storage.

I think this generates a deadlock somehow (which isn't surprising, honestly).

Tobias

 

[t.lamprecht]

I think the problem occurs here:
INFO: issuing guest-agent 'fs-freeze' command
INFO: issuing guest-agent 'fs-thaw' command

This seems to block the writes to the VM - and is generating some sort of inception - I see no way how this can be prevented...

Hmm, true, we start off the backup from the clean state after the VMs FS are frozen, which connects to the server - so yes, with a guest agent you may not be able to do this - and without it may not be in sync (albeit, we do not really have a database which could get corrupted here)

 

[iprigger]

Hi Thomas,

Hmm, true, we start off the backup from the clean state after the VMs FS are frozen, which connects to the server - so yes, with a guest agent you may not be able to do this - and without it may not be in sync (albeit, we do not really have a database which could get corrupted here)

I tend to like the guest-agent a lot - much cleaner backups

Basically, the workaround is simple: Do the backup of PBS using vzdump to a normal (NFS)-Store - and send the rest to PBS.

BTW, I'm seeing quite good numbers doing backups... especially unix vms are about 50-60% faster (even though I run a bit a weird setup with NFS to a remote room etc...)

Exchange Server is a bit faster, too - but... it's quite a big VM with lots of customers on it.... so a quite high change rate anyways.

Tobias