On Sun, Dec 22, 2013 at 02:57:27PM +0100, Paolo Bonzini wrote:
> Linux prefers WRITE SAME to UNMAP if the limits are zero, and WRITE
> SAME does not discard anything unless the device can guarantee that
> the resulting block is zero.
>
> Setting the maximum unmap block and descriptor counts to non
Linux prefers WRITE SAME to UNMAP if the limits are zero, and WRITE
SAME does not discard anything unless the device can guarantee that
the resulting block is zero.
Setting the maximum unmap block and descriptor counts to non-zero
makes Linux choose UNMAP and fixes thin provisioning on glusterfs.
