[pve-devel] qemu 2.3 : format=raw need to be explicitly defined for some storages

[Emmanuel Kasper]

On 06/09/2015 02:49 PM, Alexandre DERUMIER wrote:
> Hi,
> 
> I was testing qemu 2.3 with librbd, and I notice a warning
> 
> WARNING: Image format was not specified for 'rbd:pooltest/vm-100-disk-1:mon_host=10.5.0.16:auth_supported=none' and probing guessed raw.
>          Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
>          Specify the 'raw' format explicitly to remove the restrictions.
> 
> 
> 
> It seem that we need to pass format=raw to the drive string, or we are not able to write block0.
> 
> Don't have tested with other storages, but I think it should apply on iscsi,zfs and sheepdog too
> 

Hallo Alexandre
Yes I have just seen that with ZFS today:

qm start 103
Running as unit 103.scope.

WARNING: Image format was not specified for
'/dev/zvol/tank/vm-103-disk-1' and probing guessed raw.
         Automatically detecting the format is dangerous for raw images,
write operations on block 0 will be restricted.
         Specify the 'raw' format explicitly to remove the restrictions


Emmanuel