On Sat, Jun 08, 2013 at 12:48:52PM +1000, Chris Dunlop wrote:
> On Fri, Jun 07, 2013 at 11:54:20AM -0500, Alex Elder wrote:
>> On 06/03/2013 04:24 AM, Chris Dunlop wrote:
>>> I pulled the for-linus branch (@ 3abef3b) on top of 3.10.0-rc4, and it's
>>> letting me map a format=2 image (created under bobtail), however reading
>>> from the block device returns zeros rather than the data. The same image
>>> correctly shows data (NTFS filesystem) when mounted into kvm using librbd.
>>
>> Have you tried using a format 2 image that you created using
>> the Linux rbd environment? It would be good to know whether
>> that works for you.
>
> Sorry, how to you mean "created using the Linux rbd environment"?
> The one I was trying was created using:
>
> rbd create --format 2 xxx --size nnnnn
>
> ...then populated using qemu/librbd.
Looks like the kernel rbd and librbd aren't compatible, as at
3.10.0-rc4+ceph-client/for-linus@3abef3b vs librbd1 0.56.6-1~bpo70+1.
I can create a format=2 rbd image, map it, format and populate it using the
mapped device. I can then see that data after unmounting unmapping, then
re-mapping and re-mounting. However if I then attach that image via librbd to a
qemu-1.5.0~rc3 vm using the invocation below, the vm sees the whole device as
zeros.
Likewise, if I create a new format=2 rbd image, attach it via librbd to a
qemu-1.5.0~rc3 vm, format it and populate it, that data is thereafter visible
in the vm (e.g. after remounting etc.). But if I map that image using the
kernel client, again I get a device full of zeros.
# dpkg -l \*ceph\* \*rbd\* \*rados\* | grep ^i
ii ceph 0.56.6-1~bpo70+1 amd64 distributed storage and file system
ii ceph-common 0.56.6-1~bpo70+1 amd64 common utilities to mount and interact with a ceph storage cluster
ii librados2 0.56.6-1~bpo70+1 amd64 RADOS distributed object store client library
ii librbd1 0.56.6-1~bpo70+1 amd64 RADOS block device client library
##
## Attach disk to vm
##
# virsh attach-device test <(cat <<END
<disk type='network' device='disk'>
<driver name='qemu' type='raw'/>
<auth username='vm'>
<secret type='ceph' uuid='xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'/>
</auth>
<source protocol='rbd' name='rbd/crd-test'/>
<target dev='vdc' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x7' function='0x0'/>
</disk>
END
)
Cheers,
Chris
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