[virt-tools-list] Delayed Deletion or Creation

[Cole Robinson]

On 01/24/2016 08:15 AM, Michael A Cooper wrote:
> Hey Guys,
> 
>         How is everyone? I am not sure how to word this question but here
> goes. I have a 3 server setup and I created a nfs share so that I could do
> Live Migration across the servers. So when I create the vm with qcow2
> everything goes smooth and quick, but when I try to create with .img (Raw) it
> takes forever to create the file. Also when I try and delete an .img file (20
> gb) it has been over 20 minutes to delete it, any ideas?
> 

qcow2 files are sparse/not-fully-allocated, so while you request 20GB it's
probably only writing a few MB. The rest is filled in as the VM writes to it.

raw can do sparse as well, but 1) virt-manager doesn't default to it if you
choose raw which means it is allocating the full 20GB, and 2) even if you do
choose sparse the semantics are a bit different for NFS, not sure if it
affects your use case though:
https://serverfault.com/questions/731632/does-nfs-and-smb-support-sparse-files

- Cole