snapshot feature is not available

Medvenda

Member
Oct 5, 2016
40
0
6
35
Hello,
When i access to lxc container i find that the "take snapshot" button is disabled . Acroos Proxmox API i find the task error :

()


Task viewer: CT 111 - Snapshot

OutputStatus

Stop
TASK ERROR: snapshot feature is not available

proxmox-ve: 4.4-78 (running kernel: 4.4.35-2-pve)
pve-manager: 4.4-5 (running version: 4.4-5/c43015a5)
pve-kernel-4.2.6-1-pve: 4.2.6-36
pve-kernel-4.4.35-2-pve: 4.4.35-78
pve-kernel-4.4.21-1-pve: 4.4.21-71
lvm2: 2.02.116-pve3
corosync-pve: 2.4.0-1
libqb0: 1.0-1
pve-cluster: 4.0-48
qemu-server: 4.0-102
pve-firmware: 1.1-10
libpve-common-perl: 4.0-85
libpve-access-control: 4.0-19
libpve-storage-perl: 4.0-71
pve-libspice-server1: 0.12.8-1
vncterm: 1.2-1
pve-docs: 4.4-1
pve-qemu-kvm: 2.7.1-1
pve-container: 1.0-90
pve-firewall: 2.0-33
pve-ha-manager: 1.0-38
ksm-control-daemon: 1.2-1
glusterfs-client: 3.5.2-2+deb8u2
lxc-pve: 2.0.6-5
lxcfs: 2.0.5-pve2
criu: 1.6.0-1
novnc-pve: 0.5-8
smartmontools: 6.5+svn4324-1~pve80
zfsutils: 0.6.5.8-pve13~bpo80


Any suggestion to solve this problem ?
 

Medvenda

Member
Oct 5, 2016
40
0
6
35
I think this is because you have no Tin pool on your LVM.

see
https://pve.proxmox.com/wiki/Logical_Volume_Manager_(LVM)
i have this informations

root@pve:~# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
data pve -wi-ao---- 425.88g
root pve -wi-ao---- 96.00g
swap pve -wi-ao---- 62.00g
root@pve:~# vgs
VG #PV #LV #SN Attr VSize VFree
pve 1 3 0 wz--n- 599.87g 16.00g
root@pve:~# pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 pve lvm2 a-- 599.87g 16.00g
what's the problem ?
PS: i have a local storage (directory) with path "/var/lib/vz" contains raw machines
 
Last edited:

Nicolas Mordini

New Member
Jul 21, 2016
12
0
1
46
I understand that not all disk formats support snapshot, I'm sure qcow2 does if it does but I think raw does not.
I hope it is useful, regards
 

Medvenda

Member
Oct 5, 2016
40
0
6
35
I understand that not all disk formats support snapshot, I'm sure qcow2 does if it does but I think raw does not.
I hope it is useful, regards
I think not i have another proxmox server with raw format of lxc in lvm-thin storage and snapshot feature is available. This is not the problem. I dont understand why data is displayed with "lvs" command and on the wizard of add new lvm storage i can't find it
 

wolfgang

Proxmox Retired Staff
Retired Staff
Oct 1, 2014
6,496
496
103
As I thought you have no Thin-pool.
You have to create a thin-pool on your LV.

There are 1000 of HowTo in the net, how to build a thinpool on top of a LV.
 
  • Like
Reactions: Medvenda

Roman Shein

Member
Sep 11, 2017
15
0
21
43
Kyiv, Ukraine
I believe it make sense to bump this topic once more.
I've noticed that there is an inconsistency in treatment of LXC snapshots and backups. Proxmox "unfairly" discriminates against the containers which have bind mounts, doesn't allow snapshots for these VMs ("snapshot feature is not available" "ERROR: pct snapshot..."). Yet at the same time it is OK to backup these machines. Why?
 

Roman Shein

Member
Sep 11, 2017
15
0
21
43
Kyiv, Ukraine
A potential solution is to use
lxc.mount.entry=/path/in/host/mount_point mount_point_in_container none bind 0 0 (for details see
https://wiki.debian.org/LXC#External_mounts_inside_the_container).
The CT operates fine, yet the snapshot feature gets back to work!
The only drawback so far is that lxc.mount.entris are not visible in the GUI. I hope Proxmox team will consider addin it eventually. This would be a usable workaround.
 

wolfgang

Proxmox Retired Staff
Retired Staff
Oct 1, 2014
6,496
496
103
Hi Roman Shein,

A snapshot is at PVE a guest state at the snapshot time.
So all images must be consistent at this snapshot.
A bind-mount has no snapshot functionality.
It is a design decision that it is this way.
The LXC parameter is used anyway for bind mounts but you bypass this logic.
And a workaround will not show in the GUI.
 

Roman Shein

Member
Sep 11, 2017
15
0
21
43
Kyiv, Ukraine
Hi Roman Shein,

A snapshot is at PVE a guest state at the snapshot time.
So all images must be consistent at this snapshot.
A bind-mount has no snapshot functionality.
It is a design decision that it is this way.
The LXC parameter is used anyway for bind mounts but you bypass this logic.
And a workaround will not show in the GUI.

1) Conceptually the virtualization is about broadening the choice, increasing the freedom, not narrowing it down.
2) There is a valid business case to justify the "inconsistency". The appliance snapshots are very handy for recovering from an update gone wrong. The partial (appliance only) snapshot will allow for very granular (because of low storage requirements), near instant roll back to a good configuration. Yet in this situation you would want to rollback the appliance only, not the user data!
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get your own in 60 seconds.

Buy now!