I like this idea a lot for Ceph RBD.  I do think there should still be
support for copying snapshots to secondary storage as needed (for
transfers between zones, etc.).  I really think that this could be
part of a larger move to clarify the naming conventions used for disk
operations.  Currently "Volume Snapshots" should probably really be
called "Backups".  So having "snapshot" functionality, and a "convert
snapshot to backup/template" would be a good move.

Thank You,

Logan Barfield
Tranquil Hosting


On Mon, Feb 16, 2015 at 9:16 AM, Andrija Panic <andrija.pa...@gmail.com> wrote:
> BIG +1
>
> My team should submit some patch to ACS for better KVM snapshots, including
> whole VM snapshot etc...but it's too early to give details...
> best
>
> On 16 February 2015 at 13:01, Andrei Mikhailovsky <and...@arhont.com> wrote:
>
>> Hello guys,
>>
>> I was hoping to have some feedback from the community on the subject of
>> having an ability to keep snapshots on the primary storage where it is
>> supported by the storage backend.
>>
>> The idea behind this functionality is to improve how snapshots are
>> currently handled on KVM hypervisors with Ceph primary storage. At the
>> moment, the snapshots are taken on the primary storage and being copied to
>> the secondary storage. This method is very slow and inefficient even on
>> small infrastructure. Even on medium deployments using snapshots in KVM
>> becomes nearly impossible. If you have tens or hundreds concurrent
>> snapshots taking place you will have a bunch of timeouts and errors, your
>> network becomes clogged, etc. In addition, using these snapshots for
>> creating new volumes or reverting back vms also slow and inefficient. As
>> above, when you have tens or hundreds concurrent operations it will not
>> succeed and you will have a majority of tasks with errors or timeouts.
>>
>> At the moment, taking a single snapshot of relatively small volumes (200GB
>> or 500GB for instance) takes tens if not hundreds of minutes. Taking a
>> snapshot of the same volume on ceph primary storage takes a few seconds at
>> most! Similarly, converting a snapshot to a volume takes tens if not
>> hundreds of minutes when secondary storage is involved; compared with
>> seconds if done directly on the primary storage.
>>
>> I suggest that the CloudStack should have the ability to keep volume
>> snapshots on the primary storage where this is supported by the storage.
>> Perhaps having a per primary storage setting that enables this
>> functionality. This will be beneficial for Ceph primary storage on KVM
>> hypervisors and perhaps on XenServer when Ceph will be supported in a near
>> future.
>>
>> This will greatly speed up the process of using snapshots on KVM and users
>> will actually start using snapshotting rather than giving up with
>> frustration.
>>
>> I have opened the ticket CLOUDSTACK-8256, so please cast your vote if you
>> are in agreement.
>>
>> Thanks for your input
>>
>> Andrei
>>
>>
>>
>>
>>
>
>
> --
>
> Andrija Panić

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