>>What is the source format? If the zero clusters are actually unallocated in >>the >>source image, drive-mirror will not write those clusters either. I.e. with >>"drive-mirror sync=top", both source and target should have the same "qemu-img >>map" output.
Thanks for your reply, I had tried drive mirror (sync=full) with raw file (sparse) -> rbd (no sparse) rbd (sparse) -> rbd (no sparse) raw file (sparse) -> qcow2 on ext4 (sparse) rbd (sparse) -> raw on ext4 (sparse) Also I see that I have the same problem with target file format on xfs. raw file (sparse) -> qcow2 on xfs (no sparse) rbd (sparse) -> raw on xfs (no sparse) I only have this problem with drive-mirror, qemu-img convert seem to simply skip zero blocks. Or maybe this is because I'm using sync=full ? What is the difference between full and top ? ""sync": what parts of the disk image should be copied to the destination; possibilities include "full" for all the disk, "top" for only the sectors allocated in the topmost image". (what is topmost image ?) ----- Mail original ----- De: "Fam Zheng" <f...@redhat.com> À: "Alexandre DERUMIER" <aderum...@odiso.com> Cc: "qemu-devel" <qemu-devel@nongnu.org>, "Ceph Devel" <ceph-de...@vger.kernel.org> Envoyé: Samedi 11 Octobre 2014 09:01:18 Objet: Re: [Qemu-devel] qemu drive-mirror to rbd storage : no sparse rbd image On Wed, 10/08 13:15, Alexandre DERUMIER wrote: > 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. What is the source format? If the zero clusters are actually unallocated in the source image, drive-mirror will not write those clusters either. I.e. with "drive-mirror sync=top", both source and target should have the same "qemu-img map" output. Fam > > > 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 > > >
