Re: [QUESTION] How is snapshot size counted in secondary storage?

[Gaurav Aradhye <ga...@clogeny.com>]

Hello all,

A small update which closes this question.

Now the listSnapshots API provides the size of the snapshot precisely
(physicalsize attribute), and when I count it to match with total secondary
storage count for an account, then there is no descrepancy. This facility
is in with commit 9153b8bede3350750cb7a78891e0479cc72aa2ec.

Also the regression tests have been modified accordingly to test secondary
storage limits functionality correctly according to above mentioned changes.

Regards,
Gaurav

On Thu, Dec 11, 2014 at 3:48 AM, Mike Tutkowski <
mike.tutkowski@solidfire.com> wrote:

> Including Kelven directly on this using a different e-mail address (first
> e-mail address bounced).
>
> On Wed, Dec 10, 2014 at 3:16 PM, Mike Tutkowski <
> mike.tutkowski@solidfire.com> wrote:
>
> > Hi everyone,
> >
> > Can anyone answer these questions Gaurav has about secondary storage?
> >
> > Marcus - Perhaps you know for KVM?
> >
> > Kelven - Perhaps you know for VMware?
> >
> > Thanks!
> > Mike
> >
> > On Wed, Dec 10, 2014 at 4:55 AM, Gaurav Aradhye <
> > gaurav.aradhye@clogeny.com> wrote:
> >
> >> Thanks Mike for details reply!
> >>
> >> I checked on VMware and KVM. On KVM, after first snapshot, the secondary
> >> storage count for account increases by 1 (template + snapshot I
> suppose).
> >> After second snapshot, it again increases by 1.
> >>
> >> On VmWare, the secondary storage count remains the same irrespective of
> >> how
> >> many snapshots I create.
> >>
> >> This is clearly an issue.
> >>
> >> I have two questions.
> >>
> >> 1) How can we know the snapshot size? The size is not listed in any API.
> >> 2) Is snapshot size counted in secondary storage count (and hence
> >> considered in SS limits)? I just want to be sure here.
> >>
> >> Regards,
> >> Gaurav
> >>
> >> On Tue, Dec 9, 2014 at 11:17 AM, Mike Tutkowski <
> >> mike.tutkowski@solidfire.com> wrote:
> >>
> >> > I guess I would expect the non-zero blocks of your disk to be backed
> up
> >> the
> >> > first time, which could lead to anywhere from some small amount of
> space
> >> > all the way up to 8 GB (in your situation).
> >> >
> >> > However, you mentioned that you see 9 GB consumed, which does seem
> >> > unexpected.
> >> >
> >> > When you say your template is 8 GB, I assume that's its physical size
> >> (and
> >> > the root disk's virtual size could be larger).
> >> >
> >> > If that's the case, I would expect 8 GB to be backed up for the first
> >> > snapshot.
> >> >
> >> > On Mon, Dec 8, 2014 at 10:39 PM, Gaurav Aradhye <
> >> > gaurav.aradhye@clogeny.com>
> >> > wrote:
> >> >
> >> > > Thanks Mike!
> >> > >
> >> > > However, I am observing this in case of first snapshot also. Let me
> >> try
> >> > on
> >> > > various hypervisors to see the behavior.
> >> > >
> >> > > Regards,
> >> > > Gaurav
> >> > >
> >> > > On Tue, Dec 9, 2014 at 11:04 AM, Mike Tutkowski <
> >> > > mike.tutkowski@solidfire.com> wrote:
> >> > >
> >> > > > I'm not exactly sure how this number is calculated, but - if you
> are
> >> > > using
> >> > > > XenServer - remember that after the first snapshot for a volume,
> >> each
> >> > > > subsequent snapshot is only the blocks that have changed since the
> >> > prior
> >> > > > snapshot (this might even be true for ESX these days with
> >> CloudStack).
> >> > > >
> >> > > > That being the case, unless you change all 8 GB of blocks each
> time
> >> > > before
> >> > > > doing a snapshot, you should expect your snapshots to be < 8 GB
> >> > > > (potentially very small, if you didn't change much since the last
> >> > > > snapshot).
> >> > > >
> >> > > > On Mon, Dec 8, 2014 at 10:15 PM, Gaurav Aradhye <
> >> > > > gaurav.aradhye@clogeny.com>
> >> > > > wrote:
> >> > > >
> >> > > > > Hello,
> >> > > > >
> >> > > > > When I create a snapshot, from say, template registered through
> an
> >> > > > account,
> >> > > > > then
> >> > > > >
> >> > > > > 1) How can I know the snapshot size on secondary storage? (API
> >> > > > > listSnapshots does not specify the snapshot size)
> >> > > > >
> >> > > > > 2) How is snapshot size counted in secondary storage used by the
> >> > > account?
> >> > > > > Currently I can see secondary storage count increasing by the
> >> (number
> >> > > of
> >> > > > > snapshots) and not the snapshot size.
> >> > > > >
> >> > > > > E.g. I have template sized 8 GB. I create a snapshot from it.
> Now
> >> if
> >> > I
> >> > > > list
> >> > > > > the secondary storage used by the account, then it lists as "9"
> >> (GB).
> >> > > If
> >> > > > I
> >> > > > > create another snapshot, then it lists it as 10. It is not
> >> possible
> >> > for
> >> > > > my
> >> > > > > snapshot size to be 1 (GB) because it's created from root volume
> >> > having
> >> > > > > size 8 GB.
> >> > > > >
> >> > > > > Can I say it's a bug? Secondary storage count being listed as
> >> > (Storage
> >> > > > > other than snapshot + number of snapshots) GB.
> >> > > > >
> >> > > > > Regards,
> >> > > > > Gaurav
> >> > > > >
> >> > > >
> >> > > >
> >> > > >
> >> > > > --
> >> > > > *Mike Tutkowski*
> >> > > > *Senior CloudStack Developer, SolidFire Inc.*
> >> > > > e: mike.tutkowski@solidfire.com
> >> > > > o: 303.746.7302
> >> > > > Advancing the way the world uses the cloud
> >> > > > <http://solidfire.com/solution/overview/?video=play>*™*
> >> > > >
> >> > >
> >> >
> >> >
> >> >
> >> > --
> >> > *Mike Tutkowski*
> >> > *Senior CloudStack Developer, SolidFire Inc.*
> >> > e: mike.tutkowski@solidfire.com
> >> > o: 303.746.7302
> >> > Advancing the way the world uses the cloud
> >> > <http://solidfire.com/solution/overview/?video=play>*™*
> >> >
> >>
> >
> >
> >
> > --
> > *Mike Tutkowski*
> > *Senior CloudStack Developer, SolidFire Inc.*
> > e: mike.tutkowski@solidfire.com
> > o: 303.746.7302
> > Advancing the way the world uses the cloud
> > <http://solidfire.com/solution/overview/?video=play>*™*
> >
>
>
>
> --
> *Mike Tutkowski*
> *Senior CloudStack Developer, SolidFire Inc.*
> e: mike.tutkowski@solidfire.com
> o: 303.746.7302
> Advancing the way the world uses the cloud
> <http://solidfire.com/solution/overview/?video=play>*™*
>