Cannot create snapshot

Pest

Active Member
Jun 3, 2017
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Hi,
I have few VM under proxmox. I've created snapshots for all of them with no issues at first.
One of my VM (openmediavault) has 2 disks - 7Gb OS disk(local-lvm) + 2,5Tb storage disk(part of zfs raidz1; clicked no backup).
I have created init snapshot for it. Than added storage disk and created another snapshot. Than after a while i'd done some changes to it and wanted to snapshot it again. It gives me an error:

`TASK ERROR: zfs error: cannot create snapshot 'tank/vm-101-disk-1@update': out of space`

Other snapshots works fine. I've tried to delete second snapshot to cleanup some space, still same error.
I can make backup for it though.

My config
1x240Gb hdd (local + local-lvm)
3x2Tb hdd zfs raidz1 (tank)

local has ~20Gb free space
local-lvm has ~55Gb free space
zfs-tank has ~400Gb free space

What is the issue in my case?
 
UPD:
looks like i've found whats the issue.
tank/vm-101-disk-1 is 2,5Tb disk and its obviously not enough space to back it up.
When i remove it from VM snapshot works fine. After it I can re-add it again. VM should be down for those operations.

Its a bit unclear for me, I though snapshot honours the "no backup" flag for a disk.

My issue is fixed, but isnt it something that can be added to pve?
 
Its a bit unclear for me, I though snapshot honours the "no backup" flag for a disk.
snapshots and backup are two completely different things. A snapshot represents a point in time of a VM which includes all disks and optionally also the RAM so snapshots are not supposed to take into concern whether a disk is marked for backup or not since excluding a disk from snapshot will also exclude the disk for rollback potentially leaving dangling file system references to the now excluded disk.
 
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snapshots and backup are two completely different things. A snapshot represents a point in time of a VM which includes all disks and optionally also the RAM so snapshots are not supposed to take into concern whether a disk is marked for backup or not since excluding a disk from snapshot will also exclude the disk for rollback potentially leaving dangling file system references to the now excluded disk.
Ok, makes sense now. Backup saves all the configs and installed apps while snapshot saves actual VM state.
Thanks.
 
Last edited:

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