raw is to slow to backup. qcow2 vs vmdk? other ideas?

[nate]

I have a VM that I'm configuring as a email server (ubuntu 12.10) 1TB . I initially configured this as raw. But then I realized when baking up it takes a long, long time to shared storage. So this is an issue for me.

I know I could use a smaller disk, then re-size it, but not sure I want to go that way.

qcow2 & vmdk auto grow, so that fixes the near term before it gets big.

Which is better to use qcow2 or vmdk?

Any other ideas?

Thanks.

 

[e100]

I mostly use LVM so I have little experience with qcow2 or vmdk.

As you use up space qcow2 and vmdk will grow and eventually you end up with the same problem you are having with raw today.

One thing you can do to help with the backup issues with raw is to write zeros to the free space inside your VM.
Then use compression when backing up, those zeros will compress very well making the backup size much smaller and increasing the speed of the backup.

The last post in this thread has some good directions on writing zeros to the free space:
http://forum.proxmox.com/archive/index.php/t-9299.html