Raw VS qcow2

[masterdaweb]

Proxmox Docs suggests using Raw format for Windows VMs, because of the big performance gain.

I'd like to know if is there an advantage too using Raw format for Linux VMs, and when should we use qcow2 ?

I'm using KVM to all VMs

 

[alexskysilk]

Proxmox Docs suggests using Raw format for Windows VMs, because of the big performance gain.

I'd like to know if is there an advantage too using Raw format for Linux VMs, and when should we use qcow2 ?

I'm using KVM to all VMs

the disk format will follow your choice of backing storage.

If you're using backing storage with CoW (CoW= Copy On Write, which is what enables snapshots, backups, etc) built in, such as zfs, ceph, etc you will use raw and let the filesystems provide CoW facilities. If your using NFS or a traditional file system, you can use qcow2 since it provides those facilities in the file format.

 

[masterdaweb]

@alexskysilk , Raw format can be used with NFS too and allows clone VM at runtime.

Despite of more features that qcow may offer, I think they are useless for many people.

I think Performance gain is above any other feature (as far as I know) provided by qcow2 format. But I don't think i'm absolutly right, that's why I started this thread.

 

[alexskysilk]

@alexskysilk , Raw format can be used with NFS too and allows clone VM at runtime.

yes it can.

Despite of more features that qcow may offer, I think they are useless for many people...But I don't think i'm absolutly right, that's why I started this thread.

These ideas are contradictory. when you decide what it is thats important for you, the solution will become clear. I will only mention that speed is useless if its unreliable; not everyone uses this technology to play with.