shared LVM storage backup to PBS server, why?

[Gabor Szel]

Dear @all!

We migrated our PVE Cluster to share LVM storage.
(And we make a mistake, we didn't test everything ... backup)

previous system:

• 6x PVE host with local PVE storage
  SSDs in HW RAID or, HDDs in HW RAID
• all local storage configured as LVM-thin
• 1x PBS backup host
• All PVE host send backup to PBS, once a day (snapshot, or shutdown - incremental)

This worked very nicely!

new system:

• 4x PVE host, no local PVE storage, only 2xSSD from OS
• 1x Dell FC 12G storage (SAS SSDs)
• All PVE host use storage with FC multipath.
• we set shared LVM storage
• all hosts, and share LVM storage is working, but the snapshot is sorely lacking ...

problem:
We migrating all VMs from old system to new system.
All VM is running, everything's cool.
We add PBS to PVE cluster, PBS is connected, working.

BUT!
This is useless!

if I want to backup an LXC VM, it doesn't work:

INFO: starting new backup job: vzdump 510 --storage inv-pbs1 --node n1 --remove 0 --notes-template '{{guestname}}' --mode snapshot
INFO: Starting Backup of VM 510 (lxc)
INFO: Backup started at 2023-01-07 11:02:46
INFO: status = running
INFO: CT Name: xxxx
INFO: including mount point rootfs ('/') in backup
INFO: mode failure - some volumes do not support snapshots
INFO: trying 'suspend' mode instead
INFO: backup mode: suspend
INFO: ionice priority: 7
INFO: CT Name: xxxx
INFO: including mount point rootfs ('/') in backup
INFO: starting first sync /proc/3595788/root/ to /var/tmp/vzdumptmp5041_510
ERROR: Backup of VM 510 failed - command 'rsync --stats -h -X -A --numeric-ids -aH --delete --no-whole-file --sparse --one-file-system --relative '--exclude=/tmp/?*' '--exclude=/var/tmp/?*' '--exclude=/var/run/?*.pid' /proc/3595788/root//./ /var/tmp/vzdumptmp5041_510' failed: exit code 10
INFO: Failed at 2023-01-07 11:09:56
INFO: Backup job finished with errors
TASK ERROR: job errors

Backup task mount LXC FS to Proxmox host /var/tmp directory.
This is host local file system, only ~100Gb disk space.
This file system not have enough disk space, backup stopped ...
And if I have 2Tb LXC , will it always copy over?
It can't work! A lot of time, wasteful!
So far we have loved proxmox!
But it cannot be used on a shared storage ...
No snapshot support for shared storage system, so all backup solutions are bad.
but it's interesting because the KVM save is successful:

INFO: VM Name: xxxx
INFO: include disk 'virtio0' 'p8-r6ssd1:vm-811-disk-0' 60G
INFO: backup mode: snapshot
INFO: ionice priority: 7

Why does the snapshot work there?

 

[tom]

See https://pve.proxmox.com/pve-docs/pve-admin-guide.html#chapter_storage

=> we recommend you take a look on Ceph (but you need the right hardware if you go for Ceph).