Offsite backup - Low RAM environment

G’day,

I have a couple of systems that are running ubuntu vm’s on top of Hyper V and I was just wondering what the best solution for offsite backups are?

I currently am using EXT4 on top of LVM and have a little experience with ZFS, however, one of these VM’s has a very small amount of RAM so I am a little hesitant.

I have heard BTRFS uses less RAM but is a bore in terms of performance (it is running Nextcloud) and but should be stable in single disk configurations (the RAID is handled in the windows end).

Should I bite the bullet and use an LVM snapshot and rsync/rclone to rsync.net/object storage respectively? Should I use something like Veeam or UrBackup within the VM itself?

I am pretty sold on using ZFS on those that have enough RAM, what do you guys think the RAM cut off for ZFS would be? Though not looking forward to moving all the data around to get it into a new filesystem.

Any help would be greatly apprecitated,

Cheers

Depends on what you need in the way of performance and how large the pool is, really. It’s usually better to run ZFS on the host and let the VMs use simple filesystems like ext4 underneath, rather than the other way around.

But if you’re stuck with whatever you’ve got on the host side, and still want to run ZFS inside the VM, I’d generally advise a minimum of 2GiB allocated to the VM.

Rsync.net is very expensive but you might want to pay for it but still it wouldn’t make sense because you can’t just zfs send everything because you don’t use ZFS.

You could just use Rsync or rclone to sync data from VMs.

Is that what needs to be backed up? Just the data from VMs?

I guess you could also install Linux subsystem on Windows and that will give you Rsync and then you can Rsync all VM Disks to whatever other server you have.

How does Hyper-V handle VM backups. I kind of remember there was VM export which just copies the VHDX file elsewhere with other data. But is that used for backing up VMs?

Yeah, unfortunately as these systems are already in place I don’t have the ability to swap the host to Linux :cry: . 2GB seems doable for most of them, do I need to reduce the amount of RAM the ARC can use to prevent the VM using too much swap? On a machine running ZFS on the host I had that it was rapidly consuming swap space due to the amount of data stored in the ARC.

Regarding RSYNC.net, I would be creating a new vhdx formatted with ZFS and moving the data into it from the existing LVM + EXT4 partition (pain in the neck I know :face_holding_back_tears: ). The exporting functionality with Hyper V is very clunky and wouldn’t allow for incrementals needed for offsite backup unfortunately :cry:

Thanks again for all of the help that you guys have provided, it has made my journey with ZFS soo sooo much better.