[Qemu-devel] qemu drive-mirror to rbd storage : no sparse rbd image

[Alexandre DERUMIER]

Hi,

I'm currently planning to migrate our storage to ceph/rbd through qemu 
drive-mirror

and It seem that drive-mirror with rbd block driver, don't create a sparse 
image. (all zeros are copied to the target rbd).

Also note, that it's working fine with "qemu-img convert" , the rbd volume is 
sparse after conversion.


Could it be related to the "bdrv_co_write_zeroes" missing features in 
block/rbd.c ?

(It's available in other block drivers (scsi,gluster,raw-aio) , and I don't 
have this problem with theses block drivers).



Regards,

Alexandre Derumier