Good idea, Tim. Thanks

On Thu, Dec 19, 2013 at 3:21 PM, Tim Mackey <tmac...@gmail.com> wrote:

> Mike, you might want to post this to xs-devel on XenServer.org.  Some of
> the storage engineers there would be in s better position to diagnose.
> On Dec 19, 2013 5:10 PM, "Mike Tutkowski" <mike.tutkow...@solidfire.com>
> wrote:
>
> > Hi,
> >
> > I have been experimenting with VM snapshots on XenServer and have
> noticed a
> > problem that I hope someone might be able to shed some light on.
> >
> > In a normal flow of taking a VM snapshot, reverting to it, then deleting
> > the VM snapshot, I have observed the following (which looks just fine):
> >
> > *SR:*
> >
> > uuid ( RO)                : 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >           name-label ( RW): Test
> >     name-description ( RW): iSCSI SR [10.10.8.108
> > (iqn.2010-01.com.solidfire:3y8w.test.15; LUN 0:
> > 337938770000000ff47acc0100000000: 93.1 GB (SolidFir))]
> >                 host ( RO): XenServer-6.1-Tut-2
> >                 type ( RO): lvmoiscsi
> >         content-type ( RO):
> >
> >
> >    - *Before VM snap:*
> >
> >
> > *Active:*
> >
> > uuid ( RO)                : b4587018-9679-4fe7-ba72-5523cb988cec
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> >
> >    - *After VM snap:*
> >
> >
> > *Base copy (contains the data of the previously active VDI):*
> >
> > uuid ( RO)                : d167952d-deb4-4942-9ea8-c8b3777d885e
> >           name-label ( RW): base copy
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): true
> >
> > *Snapshot:*
> >
> > uuid ( RO)                : 613dc799-cf69-445a-a2fe-611653e0b0c9
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> > *Active (has the same UUID as the previously active VDI):*
> >
> > uuid ( RO)                : b4587018-9679-4fe7-ba72-5523cb988cec
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> >
> >    - *After revert to VM snap:*
> >
> >
> > *Base copy:*
> >
> > uuid ( RO)                : d167952d-deb4-4942-9ea8-c8b3777d885e
> >           name-label ( RW): base copy
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): true
> >
> > *Snapshot (this VDI is un-touched):*
> >
> > uuid ( RO)                : 613dc799-cf69-445a-a2fe-611653e0b0c9
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> > *Active (this is a new VDI - the old active VDI was deleted):*
> >
> > uuid ( RO)                : b21284fa-347a-459a-a8bf-0fcd7717a134
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> >
> >    - *After deleting VM snap:*
> >
> >
> > *Active (the snapshot is gone as is the base copy...the base copy was
> > rolled up into this VDI):*
> >
> > uuid ( RO)                : b21284fa-347a-459a-a8bf-0fcd7717a134
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 2a061111-a8c8-11db-4a8b-f8d519f9ac3e
> >         virtual-size ( RO): 16106127360
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> > Now, in my case, where I create an SR on the fly (in response to
> attaching
> > a CloudStack volume to a VM on XenServer for the first time) to house a
> > single VDI (which has guaranteed IOPS), I see the following erroneous
> > behavior when it comes to hypervisor snapshots:
> >
> > *SR:*
> >
> > uuid ( RO)                : 70e06f08-2c9d-f9cf-4e64-2f064c11325a
> >           name-label ( RW): /iqn.2010-01.com.solidfire:3y8w.test.19/0
> >     name-description ( RW): /iqn.2010-01.com.solidfire:3y8w.test.19/0
> >                 host ( RO): XenServer-6.1-Tut-2
> >                 type ( RO): lvmoiscsi
> >         content-type ( RO): user
> >
> >
> >    - *Before VM snap:*
> >
> >
> > *Active:*
> >
> > uuid ( RO)                : 067572a8-fa4d-45b5-9365-2d7790a4b202
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 70e06f08-2c9d-f9cf-4e64-2f064c11325a
> >         virtual-size ( RO): 10737418240
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> >
> >    - *After VM snap (this appears just fine):*
> >
> >
> > *Base copy:*
> >
> > uuid ( RO)                : 71d39b5b-6c90-4aa9-adbf-71b226652081
> >           name-label ( RW): base copy
> >     name-description ( RW):
> >              sr-uuid ( RO): 70e06f08-2c9d-f9cf-4e64-2f064c11325a
> >         virtual-size ( RO): 10737418240
> >             sharable ( RO): false
> >            read-only ( RO): true
> >
> > *Snapshot:*
> >
> > uuid ( RO)                : afc66ec7-5493-4772-9318-6f72c9d971f8
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 70e06f08-2c9d-f9cf-4e64-2f064c11325a
> >         virtual-size ( RO): 10737418240
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> > *Active:*
> >
> > uuid ( RO)                : 067572a8-fa4d-45b5-9365-2d7790a4b202
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 70e06f08-2c9d-f9cf-4e64-2f064c11325a
> >         virtual-size ( RO): 10737418240
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> >
> >    - *After a failed revert to VM snap:*
> >
> >
> > uuid ( RO)                : afc66ec7-5493-4772-9318-6f72c9d971f8
> >           name-label ( RW): i-2-21-VM-DATA
> >     name-description ( RW):
> >              sr-uuid ( RO): 70e06f08-2c9d-f9cf-4e64-2f064c11325a
> >         virtual-size ( RO): 10737418240
> >             sharable ( RO): false
> >            read-only ( RO): false
> >
> > Somehow the base copy and active VDI have both been deleted and the
> > snapshot VDI is the only remaining VDI.
> >
> > I would have expected the active VDI to be deleted and a new VDI (which
> is
> > initially empty) to take its place as the active VDI. The snapshot should
> > not be touched and the base copy should not be deleted.
> >
> > Does anyone have any insight as to why this may be happening?
> >
> > Thanks!
> >
> > --
> > *Mike Tutkowski*
> > *Senior CloudStack Developer, SolidFire Inc.*
> > e: mike.tutkow...@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.tutkow...@solidfire.com
o: 303.746.7302
Advancing the way the world uses the
cloud<http://solidfire.com/solution/overview/?video=play>
*™*

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