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References: <CEA035B5.59166%kelven.yang@citrix.com>
	<068997F3-481A-4974-A81D-A83F1D10C55C@netapp.com>
Date: Thu, 7 Nov 2013 14:15:48 -0700
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 <CACOnxCjzcxT5tb4LGQYMciQKMkvXn2gx=Tnf8O6yBgR=JV6q+Q@mail.gmail.com>
Subject: Re: Bug? Should we allow detaching volumes when VMs have snapshots
From: Mike Tutkowski <mike.tutkowski@solidfire.com>
To: "dev@cloudstack.apache.org" <dev@cloudstack.apache.org>
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I can see the appeal in consistent behavior, but I'm not sure we want
CloudStack to always follow a least-common-denominator approach.

Personally I recommend we leave XenServer's functionality here as is.


On Thu, Nov 7, 2013 at 6:14 AM, SuichII, Christopher <Chris.Suich@netapp.co=
m
> wrote:

> Thanks for replying, Kelvin.
>
> Now, should we only not allow this on VMWare, or should we prohibit it on
> XenServer as well. It appears to work fine on XenServer, but it may be a
> good idea to have a consistent experience, regardless of hypervisor.
>
> -Chris
> --
> Chris Suich
> chris.suich@netapp.com
> NetApp Software Engineer
> Data Center Platforms =E2=80=93 Cloud Solutions
> Citrix, Cisco & Red Hat
>
> On Nov 6, 2013, at 9:09 PM, Kelven Yang <kelven.yang@citrix.com> wrote:
>
> > We should dis-allow detaching volume from VM when it has VM snapshots.
> > VMware keeps VM snapshot meta information at VM basis, disk membership
> > change behind its back will cause problem and it does not provide
> official
> > API to manipulate at volume level for a VM snapshot.
> >
> > This is a bug
> >
> > Kelven
> >
> > On 11/6/13, 5:58 AM, "SuichII, Christopher" <Chris.Suich@netapp.com>
> wrote:
> >
> >> Bumping this. I believe we need the imput of a VMWare expert, please.
> >>
> >> -Chris
> >> --
> >> Chris Suich
> >> chris.suich@netapp.com
> >> NetApp Software Engineer
> >> Data Center Platforms =C2=AD Cloud Solutions
> >> Citrix, Cisco & Red Hat
> >>
> >> On Nov 5, 2013, at 1:46 PM, Mike Tutkowski <
> mike.tutkowski@solidfire.com>
> >> wrote:
> >>
> >>> OK, well, depending on if we can or can't get a VMware person to chim=
e
> >>> in
> >>> on this issue, we may have to disallow disks from being detached from
> >>> VMware VMs with snapshots in 4.3.
> >>>
> >>>
> >>> On Tue, Nov 5, 2013 at 11:44 AM, SuichII, Christopher <
> >>> Chris.Suich@netapp.com> wrote:
> >>>
> >>>> Correct.
> >>>>
> >>>> #6 FAILS with VMWare and SUCCEEDS with Xen
> >>>>
> >>>> --
> >>>> Chris Suich
> >>>> chris.suich@netapp.com
> >>>> NetApp Software Engineer
> >>>> Data Center Platforms =C2=AD Cloud Solutions
> >>>> Citrix, Cisco & Red Hat
> >>>>
> >>>> On Nov 5, 2013, at 1:35 PM, Mike Tutkowski
> >>>> <mike.tutkowski@solidfire.com>
> >>>> wrote:
> >>>>
> >>>>> I assume 6 fails with VMware, as well?
> >>>>>
> >>>>> Is Xen OK with 6?
> >>>>>
> >>>>>
> >>>>> On Tue, Nov 5, 2013 at 11:26 AM, SuichII, Christopher <
> >>>>> Chris.Suich@netapp.com> wrote:
> >>>>>
> >>>>>> FWIW, after looking into this more with Xen, when the VM is restor=
ed
> >>>>>> in
> >>>>>> step 4, it simply no longer has the volume attached, so this appea=
rs
> >>>>>> to
> >>>>>> really be a VMWare issue. Any VMWare experts out there know how we
> >>>>>> can
> >>>>>> handle this?
> >>>>>>
> >>>>>> -Chris
> >>>>>> --
> >>>>>> Chris Suich
> >>>>>> chris.suich@netapp.com
> >>>>>> NetApp Software Engineer
> >>>>>> Data Center Platforms =C2=AD Cloud Solutions
> >>>>>> Citrix, Cisco & Red Hat
> >>>>>>
> >>>>>> On Nov 5, 2013, at 1:05 PM, SuichII, Christopher <
> >>>> Chris.Suich@netapp.com>
> >>>>>> wrote:
> >>>>>>
> >>>>>>> We currently don=C2=B9t allow volumes to be attached to VMs with
> >>>>>>> snapshots
> >>>>>> and allowing volumes to be detached causes quite a bug:
> >>>>>>>
> >>>>>>> 1) Attach a data disk to a VM
> >>>>>>> 2) Snapshot the VM
> >>>>>>> 3) Detach the data disk
> >>>>>>> 4) Attempt to restore the VM from the snapshot =E2=80=B9 FAILS si=
nce the
> >>>>>>> data
> >>>>>> disk is no longer there, although it is expected to be
> >>>>>>> 5) Attempt to re-attach the volume to the VM =E2=80=B9 FAILS sinc=
e you
> >>>>>>> cannot
> >>>>>> attach volumes to VMs with snapshots
> >>>>>>> 6) Attempt to delete the VM snapshot =E2=80=B9 FAILS since the da=
ta disk is
> >>>>>>> no
> >>>>>> longer there, although it is expected to be
> >>>>>>>
> >>>>>>> I have verified the above steps on VMWare, however Xen does not
> >>>>>>> appear
> >>>>>> to fail on step 4, presumably because VMWare handles snapshots qui=
te
> >>>>>> differently than Xen.
> >>>>>>>
> >>>>>>> Does anyone else have any thoughts on whether this is a bug or no=
t?
> >>>> IMO,
> >>>>>> on VMWare, this set of steps can get users into a state where they
> >>>>>> can
> >>>> no
> >>>>>> longer attach new data disks to their VM, so it appears to be a bu=
g
> >>>>>> of
> >>>> some
> >>>>>> kind.
> >>>>>>>
> >>>>>>> -Chris
> >>>>>>> --
> >>>>>>> Chris Suich
> >>>>>>> chris.suich@netapp.com
> >>>>>>> NetApp Software Engineer
> >>>>>>> Data Center Platforms =C2=AD Cloud Solutions
> >>>>>>> Citrix, Cisco & Red Hat
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> *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=3Dplay>
> >>>>> * *
> >>>>
> >>>>
> >>>
> >>>
> >>> --
> >>> *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=3Dplay>
> >>> * *
> >>
> >
>
>


--=20
*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=3Dplay>
*=E2=84=A2*

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