Backing up to NFS share on ZFS

IndyJ

I'm testing XO. I have an NFS server with ZFS (compression + deduplication enabled).

Would backing up to this nfs share cause problems for backups & restores?

HeMaN

@indyj have the same nfs on zfs setup here (minus deduplication) running on a truenas box.
xcp-ng using the nfs share for backups is working fine for me

olivierlambert

Yeah dedup could cost a lot. Maybe it's better to enable it for a backup storage for XO backups, not for your VMs.

IndyJ

Not being a ZFS expert here is an oddity: I have two old servers I use for backups. One is NFS with XFS filesystem (testing XO backups). The second is NFS with ZFS.

I copied my data from the server with XFS to the one using ZFS via rsync: A 17 Terabyte NFS/XFS share used only approximately 7 Terabytes on the ZFS server.

However If I backup data via XO to the NFS share on the ZFS system I don't seem to save space compared to backing up to NFS on the XFS filesystem.

I'm using lz4 compression & Dedupe on the ZFS system..

iLix

@indyj

What does zpool list show from the cli? Looking for dedup-rate on the dataset that holds the backups.

Forza

@indyj Probably when you use rsync, the files are transferred with larger blocks with few fsyncs. Perhaps when XO does it it is 4k transfers with fsync between each, which limits compressability a lot. Just a thought.

IndyJ

Thanks for the tips.
When I try to restore an individual file from the server using ZFS compression & dedupe XOA gives me an error: "Error while scanning disk"

I'm wondering if the compression or dedupe is the likely cause. My money is on the Deduplication. Any thoughts on this?

IndyJ

@indyj So I went to the logs and pasted the command directly into the shell. while the vhd file does exist the mount point does not.

The command assumes a temporary directory within /tmp that is not getting created by the script.

If I create the directory and paste the command into the shell the vhd does mount.

IndyJ

@indyj The file restore issue was due to installing XO on FreeBSD (fine for VM restores, not file extraction).

I then installed XO on Ubuntu 20, and this worked for restoring files from Linux VMs but not Windows VMs.
Then I installed on CentOS 8 and had the same problem as Ubuntu.

I then installed on Fedora 34 and everthing works fine.