Container Backups - No downtime?

[KarlB]

I am currently running Proxmox 4.4 with various containers. I have a weekly backup set up, which takes quite a while to run to an off-site NFS share.

I'm using the 'snapshot' mode, which the documentation says offers the lowest operation downtime. I notice that this mode makes a container unavailable for a minute or two usually, at some point in the backup cycle. Obviously I can't predict when that will happen, which can be problematic.

Is there any way to speed up this downtime, or is there a better backup method that I should consider? All I really need is an image of the containers to use in a disaster. They don't need to be updated regularly (I don't mind having to re-apply upgrades after a disaster). I have the data for my servers backed up separately.

Currently the backup is so slow (22 hours) that I am concerned a restore might be slower than simply setting up a fresh container and reconfiguring it.

 

[denos]

If you're using ZFS, you can create snapshots of a live filesystem (no pause / downtime). Snapshots are always crash consistent and can be used for restore or rollback directly on the server. They are generated very quickly (seconds) and can be kept indefinitely (storage space dependent). You can also "zfs send" the snapshots to a file which can be copied off site. If you have the option of using ZFS on the receiving side, you can keep the filesystem replicated (on say an hourly schedule) off-site with multiple off-site recovery points as a bonus.

 

[KarlB]

I will look into ZFS on other servers, but I'm not using it currently on the server in question. I have LVM set up running EXT4, so I suppose I could use LVM for the backup, but I expect that I'm going to have to set this up manually.

 

[denos]

Sure, with LVM you can create a snapshot but you'll need some free space to hold the write area while the filesystem is locked for the backup. LVM snapshots have a significant performance penalty so they may not be a great option depending on how much disk write your environments see.

Another option you can consider is converting the VMs to qcow2 backed storage which also supports snapshots.

It's a painful learning curve, but I really encourage you to invest in learning ZFS. It's an incredible piece of technology and has (at least for me) made other options seem archaic.

 

[CharlesErickT]

It's a painful learning curve, but I really encourage you to invest in learning ZFS. It's an incredible piece of technology and has (at least for me) made other options seem archaic.

I also recommend this.

We have a custom made backup script that creates a ZFS snapshot and using borgbackup backup the snapshot at the file system to a NAS. With this we can restore a single file or a whole container if needed. The whole thing is made while the container is online.
Even if you are using LVM, you could do the same.

The issue is that the proxmox backup system is not incremental therefore if the container is big it can take a long time.