Hi Mihai,

it looks rather strange in ceph snapshot, the size of snapshot is bigger
than the size of original images..
Original Image actual used size is 684M w/ provisioned 20G
but the snapshot  actual used size is ~18G w/ provisioned 20G

any ideas?

==
[root@compute2 ~]# rbd du CentOS3 -p storage1
warning: fast-diff map is not enabled for CentOS3. operation may be slow.
NAME    PROVISIONED USED
CentOS3      20480M 684M

[root@compute2 ~]# rbd du CentOS3@snap1 -p storage1
warning: fast-diff map is not enabled for CentOS3. operation may be slow.
NAME          PROVISIONED   USED
CentOS3@snap1      20480M 18124M
==
qemu-img info rbd:storage1/CentOS3
image: rbd:storage1/CentOS3
file format: raw
virtual size: 20G (21474836480 bytes)
disk size: unavailable
cluster_size: 4194304
Snapshot list:
ID        TAG                 VM SIZE                DATE       VM CLOCK
snap1     snap1                   20G 1970-01-01 08:00:00   00:00:00.000


On Thu, Jan 28, 2016 at 7:09 PM, Mihai Gheorghe <[email protected]> wrote:

> As far as i know, snapshotting with qemu will download a copy of the image
> on local storage and then upload it into ceph. At least this is the default
> behaviour when taking a snapshot in openstack of a running instance. I
> don't see why it would be any different with qemu-kvm. You must use the rbd
> snap feature to make a copy on write clone of the image.
> On 28 Jan 2016 12:59, "Bill WONG" <[email protected]> wrote:
>
>> Hi Simon,
>>
>> how you manage to preform snapshot with the raw format in qemu-kvm VMs?
>> and i found some issues with libvirt virsh commands with ceph:
>> --
>> 1) create storage pool with ceph via virsh
>> 2) create a vol via virsh - virsh vol-create-as rbdpool VM1 100G
>>
>> problem is here.. if we directly create vol via qemu-img create -f rbd
>> rbd:rbdpool/VM1 100G, then virsh is unable to find the vol. - virsh
>> vol-list rbdpool command is unable to list the vol, it looks such commands
>> - rbd, virsh and qemu-img creating images are not synced with each other...
>>
>> cloud you please let me know how you use the ceph as backend storage of
>> qemu-kvm, as if i google it, most of the ceph application is used for
>> OpenStack, but not simply pure qemu-kvm. as if setting up Glnace and Cinder
>> is troublesome...
>>
>> thank you!
>>
>>
>> On Thu, Jan 28, 2016 at 5:23 PM, Simon Ironside <[email protected]>
>> wrote:
>>
>>> On 28/01/16 08:30, Bill WONG wrote:
>>>
>>> without having qcow2, the qemu-kvm cannot make snapshot and other
>>>> features.... anyone have ideas or experiences on this?
>>>> thank you!
>>>>
>>>
>>> I'm using raw too and create snapshots using "rbd snap create"
>>>
>>> Cheers,
>>> Simon
>>>
>>
>>
>> _______________________________________________
>> ceph-users mailing list
>> [email protected]
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
>>
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