VM Migration - skip local disk?

[Jospeh Huber]

Hi,

we want to setup a qemu vm with 2 disks on Proxmox 5.
Disk 1 CEPH
Disk 2 local-lvm (big disk with temporary data)
We want to speed up the migration, the temporary data can be lost after the migration.

Is there a possibilty in Proxmox to skip the local disk 2 during migration?

I thought in the advanced properties "no backup" or "skip replication" does the trick... but the disk 2 is always copied during the migration.

I understand that the disk must exists on the target host and must be created once manually on the target host.

A possible solution would be NFS but we do not want to use a network filesystem for the temporary data...

 

[mira]

You can create a directory storage and mark it shared and use that for your 2nd disk. But you'll have to make sure it exists, has the same size and everything on all nodes you want to migrate between. And if you live migrate make sure your VM handles the changing data well.

 

[Jospeh Huber]

Thanks for your answer.

Just to understand it:
On the shared directory storage I have to put the disk image (on all target nodes). During migration all Disks on shared storages are skipped.

Right?

 

[Jospeh Huber]

Hm,

... it is not possible to set shared on a directory in the gui - I tried it on local for testing
https://pve.proxmox.com/pve-docs/chapter-pvesm.html#_storage_types

 

[mira]

It's possible to set it in the GUI. Which version are you running?

 

[Jospeh Huber]

Version 5.3.8.
I tried it on the local directory storage, I can select "shared" but OK is not active.
Because I have no free space at the moment and I have learned it is not possible to reduce my lvm-thin storage :-((
So the only way for me is to add some physical disks.

 

[mira]

It should work, there must be something else missing. But you should not mark 'local' as shared but rather create a different directory storage for your disks. If you migrate with an ISO that's on local (marked 'shared') and not available on the other node it will be problematic for example.

 

[Jospeh Huber]

OK, I will test it with dedicated additional physical disks ...

 

[Jospeh Huber]

Hi,

I have tested and verified it with additional phyiscal disks for the transient storage.
The solution with a local directory storage marked as shared works for me.
The only thing to keep in mind, you have to create the disk for the transient storage once manually for all migration targets.
Since I have used qcow2 files on ext4, it was a simple "scp diskfile targetnode:diskfile"...