qcow2 on CephFS versus RBD

[some-admins]

Hello,

we wonder which of the following two setups might be the better choice for using Proxmox VE with Ceph:

• usual: RBD
• less usual: qcow2 on CephFS

The second setup was mentioned in Thread.

What pros and cons do you come up with?

Cedric

 

[tom]

RBD.

qcow2 on CephFS does not make sense for me.

 

[Alwin]

To elaborate on Tom's answer. Qcow2 is a copy-on-write (COW) file, that will create double writes on CephFS. This is counter productive for performance. And is a redundant layer, as RBD is already suited for VM/CT image storage.