Snapshot feature not available

[jermudgeon]

I'm running the latest PVE with containers backed by CEPH. Somewhere in the past I stopped being able to snapshot containers. Backup jobs *can and do* make snapshots, but external tools are failing — for example,

INFO: filesystem type on dumpdir is 'ceph' -using /var/tmp/vzdumptmp547208_105 for temporary files
INFO: Starting Backup of VM 105 (lxc)
INFO: Backup started at 2024-03-29 00:00:00
INFO: status = running
INFO: CT Name: grafana01
INFO: including mount point rootfs ('/') in backup
INFO: excluding bind mount point mp0 ('/mnt/grafana') from backup (not a volume)
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: create storage snapshot 'vzdump'
Creating snap: 10% complete...
Creating snap: 100% complete...done.
/dev/rbd6
INFO: creating vzdump archive '/mnt/pve/cephfs/dump/vzdump-lxc-105-2024_03_29-00_00_00.tar.zst'

but

# pct snapshot 105 testsnap -description "Testing LXC snapshot on ceph"
snapshot feature is not available

here's the LXC storage config:
rootfs: ceph_vm_rep:vm-105-disk-0,size=16G

and here's the storage config:

rbd: ceph_vm_rep
        content images,rootdir
        krbd 1
        pool ceph_vm_rep

According to the guide https://pve.proxmox.com/pve-docs/pve-admin-guide.html#chapter_storage ceph should be snapshottable -- and used to be.

Any ideas of where to go from here? Is it a missing attribute in the ceph pool config post upgrade to 17 or 18? I've been using containers for almost 10 years and could snapshot them in the past!

 

[bbgeek17]

Backup snapshot is not the same thing as volume/vm snapshot.
I think the clue is in the backup log - /mnt/graphana is not a volume, so it cant be snapshotted. I believe PVE requires all storage parts of the VM to be able to take snapshot.
Try to snapshot with mp0 removed.

---

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[jermudgeon]

Try to snapshot with mp0 removed.

---

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

100% correct. I found the unimplemented feature request here:
https://bugzilla.proxmox.com/show_bug.cgi?id=1007
and this discussion
https://forum.proxmox.com/threads/why-do-bind-mounts-prevent-snapshots.85495/

Annoyingly, the mount points are cephfs, which supports snapshots. I'm not sure mounting a host directory using lxc.mount.entry, is a good idea, as I'm using lxc.idmap