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Re: [Qemu-devel] qemu drive-mirror to rbd storage : no sparse rbd image
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] qemu drive-mirror to rbd storage : no sparse rbd image |
Date: |
Sun, 12 Oct 2014 15:02:12 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 |
Il 08/10/2014 13:15, Alexandre DERUMIER ha scritto:
> 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).
Lack of bdrv_co_write_zeroes is why detect-zeroes does not work.
Lack of bdrv_get_block_status is why sparse->sparse does not work
without detect-zeroes.
Paolo
Re: [Qemu-devel] qemu drive-mirror to rbd storage : no sparse rbd image,
Paolo Bonzini <=