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Posted to users@cloudstack.apache.org by James Kahn <jk...@idea11.com.au> on 2012/08/23 12:47:22 UTC

CloudStack and XenServer 6.0.2 - stray snapshots on primary storage

Stray CloudStack generated snapshots on primary storage are causing
significant storage use on our XenServer environment. Is this expected
behaviour, a bug, or are we encountering an environmental issue? Is
anybody else seeing this?

One particular storage volume has over 1TB in use, with 659GB allocated ­
so this is a real issue for us. On that volume a 400GB VDI consumes 800GB
- 400GB for its base disk, and 400GB for the snapshot disk.

Pretty much every primary storage volume is affected. Snapshots are
exported successfully to secondary storage.

Some details on our environment:
CloudStack 3.0.1
XenServer 6.0.2
iSCSI primary storage (CloudStack managed)

The snapshots also seem to be recently current, as shown:

# xe vdi-list sr-uuid=1ddf05ad-133e-a275-90de-8b03fb69d114
is-a-snapshot=true params=uuid,name-label,snapshot-time
uuid ( RO)             : fb9210b9-25e5-46fd-a747-26e0dc536981
       name-label ( RW):
034ef007-b6a5-40f0-81a0-6f59953a59eb_ROOT-1240_20120423023335
    snapshot-time ( RO): 20120423T02:33:37Z


uuid ( RO)             : ea5392b0-8921-46ca-b74f-c16aa8e78466
       name-label ( RW): Template routing-1
    snapshot-time ( RO): 20120404T05:10:49Z


uuid ( RO)             : eba80a35-2acc-4228-905d-380a074135de
       name-label ( RW):
511f0f27-d130-4bf3-801d-3c2248efcfe0_DATA-1229_20120822180201
    snapshot-time ( RO): 20120822T18:02:04Z


uuid ( RO)             : 420c397e-8828-4b80-88ff-1db141cc7d16
       name-label ( RW): Template 98255702-1359-42ae-b635-ad7eacd09e5c
    snapshot-time ( RO): 20120411T23:28:35Z


uuid ( RO)             : b606c514-a042-4493-a0a7-07c7c5f66d3a
       name-label ( RW):
511f0f27-d130-4bf3-801d-3c2248efcfe0_ROOT-1229_20120822180201
    snapshot-time ( RO): 20120822T18:02:21Z


uuid ( RO)             : 14a75d57-8e1b-4ee7-b1b8-d069362332e9
       name-label ( RW): Template 5978eab4-166c-42f1-aeb6-a4d6bb8bb5f9
    snapshot-time ( RO): 20120412T05:48:58Z


uuid ( RO)             : 90559f54-e35a-48e3-9ce0-5e9d8b4e5587
       name-label ( RW):
ff484c2e-2b8c-4c73-9b54-da404cfa962e_ROOT-1232_20120822150201
    snapshot-time ( RO): 20120822T15:02:04Z


Any ideas?

Thanks,
JK.





Re: CloudStack and XenServer 6.0.2 - stray snapshots on primary storage

Posted by James Kahn <jk...@idea11.com.au>.
Hi Anthony,

Thanks for that explanation. I don't think that's what's happening here
though. This is definitely occurring from CloudStack snapshots rather than
provisioning. The 400GB disk is a data disk. It's very heavily used so it
wouldn't surprise me if every block has been touched by the guest VM. It
has a daily scheduled snapshot.

I've run through this scenario with a test VM/disk. It only has a 50GB
root disk.
- Provision VM - creates root disk (e.g. ROOT-1234)
- Snapshot disk
- Snapshot process creates XS snapshot (GUID_ROOT-1234_timestampA)
- Snapshot is copied to secondary storage
- Snapshot operation ends, XS snapshot (GUID_ROOT-1234_timestampA) remains
on primary storage

Performing a second snapshot operation does the following:
- Snapshot disk
- Snapshot process creates XS snapshot (GUID_ROOT-1234_timestampA)
- Snapshot is copied to secondary storage
- Snapshot process deletes previous XS snapshot
(GUID_ROOT-1234_timestampA) from primary storage.
- Snapshot operation ends, XS snapshot (GUID_ROOT-1234_timestampA) remains
on primary storage


Subsequently, deleting both snapshots from CloudStack does not remove the
stray snapshot from primary storage. It's now 36 hours after I ran this
test and snapshot is still present on primary storage.

Thanks,
JK



-----Original Message-----
From: Anthony Xu <Xu...@citrix.com>
Reply-To: "cloudstack-users@incubator.apache.org"
<cl...@incubator.apache.org>
Date: Saturday, 25 August 2012 2:06 AM
To: "cloudstack-users@incubator.apache.org"
<cl...@incubator.apache.org>
Subject: RE: CloudStack and XenServer 6.0.2 - stray snapshots on primary
storage

>
>Hi James,
>
>For root disk thin-provision, some snapshots are used as templates.
>
>After you create a VM1 on a template, the VHD chain looks like,
>
>     (base disk)
>     /         \
>(template)   (disk for vm1)
>
>After you create a VM2 on the same template
>     (base disk)
>     /         \            \
>(template)   (disk for vm1)  (disk for vm2)
>
>
>This is only for root disk derived from template. In this way, CloudStack
>can deploy VM fast, no full disk copy
>
>> so this is a real issue for us. On that volume a 400GB VDI consumes
>> 800GB
>> - 400GB for its base disk, and 400GB for the snapshot disk.
>
>Is a root disk?
>What's the template size, Have you shrunk the template before uploading
>to CloudStack? 
>A shrunk VHD file has the size about space being used.
>
>-Anthony
>
>
>
>
>> -----Original Message-----
>> From: James Kahn [mailto:jkahn@idea11.com.au]
>> Sent: Thursday, August 23, 2012 3:47 AM
>> To: cloudstack-users@incubator.apache.org
>> Subject: CloudStack and XenServer 6.0.2 - stray snapshots on primary
>> storage
>> 
>> Stray CloudStack generated snapshots on primary storage are causing
>> significant storage use on our XenServer environment. Is this expected
>> behaviour, a bug, or are we encountering an environmental issue? Is
>> anybody else seeing this?
>> 
>> One particular storage volume has over 1TB in use, with 659GB allocated
>> 
>> so this is a real issue for us. On that volume a 400GB VDI consumes
>> 800GB
>> - 400GB for its base disk, and 400GB for the snapshot disk.
>> 
>> Pretty much every primary storage volume is affected. Snapshots are
>> exported successfully to secondary storage.
>> 
>> Some details on our environment:
>> CloudStack 3.0.1
>> XenServer 6.0.2
>> iSCSI primary storage (CloudStack managed)
>> 
>> The snapshots also seem to be recently current, as shown:
>> 
>> # xe vdi-list sr-uuid=1ddf05ad-133e-a275-90de-8b03fb69d114
>> is-a-snapshot=true params=uuid,name-label,snapshot-time
>> uuid ( RO)             : fb9210b9-25e5-46fd-a747-26e0dc536981
>>        name-label ( RW):
>> 034ef007-b6a5-40f0-81a0-6f59953a59eb_ROOT-1240_20120423023335
>>     snapshot-time ( RO): 20120423T02:33:37Z
>> 
>> 
>> uuid ( RO)             : ea5392b0-8921-46ca-b74f-c16aa8e78466
>>        name-label ( RW): Template routing-1
>>     snapshot-time ( RO): 20120404T05:10:49Z
>> 
>> 
>> uuid ( RO)             : eba80a35-2acc-4228-905d-380a074135de
>>        name-label ( RW):
>> 511f0f27-d130-4bf3-801d-3c2248efcfe0_DATA-1229_20120822180201
>>     snapshot-time ( RO): 20120822T18:02:04Z
>> 
>> 
>> uuid ( RO)             : 420c397e-8828-4b80-88ff-1db141cc7d16
>>        name-label ( RW): Template 98255702-1359-42ae-b635-ad7eacd09e5c
>>     snapshot-time ( RO): 20120411T23:28:35Z
>> 
>> 
>> uuid ( RO)             : b606c514-a042-4493-a0a7-07c7c5f66d3a
>>        name-label ( RW):
>> 511f0f27-d130-4bf3-801d-3c2248efcfe0_ROOT-1229_20120822180201
>>     snapshot-time ( RO): 20120822T18:02:21Z
>> 
>> 
>> uuid ( RO)             : 14a75d57-8e1b-4ee7-b1b8-d069362332e9
>>        name-label ( RW): Template 5978eab4-166c-42f1-aeb6-a4d6bb8bb5f9
>>     snapshot-time ( RO): 20120412T05:48:58Z
>> 
>> 
>> uuid ( RO)             : 90559f54-e35a-48e3-9ce0-5e9d8b4e5587
>>        name-label ( RW):
>> ff484c2e-2b8c-4c73-9b54-da404cfa962e_ROOT-1232_20120822150201
>>     snapshot-time ( RO): 20120822T15:02:04Z
>> 
>> 
>> Any ideas?
>> 
>> Thanks,
>> JK.
>> 
>> 
>> 
>
>



RE: CloudStack and XenServer 6.0.2 - stray snapshots on primary storage

Posted by Anthony Xu <Xu...@citrix.com>.
Hi James,

For root disk thin-provision, some snapshots are used as templates.

After you create a VM1 on a template, the VHD chain looks like,

     (base disk)
     /         \
(template)   (disk for vm1) 

After you create a VM2 on the same template
     (base disk)
     /         \            \
(template)   (disk for vm1)  (disk for vm2)


This is only for root disk derived from template. In this way, CloudStack can deploy VM fast, no full disk copy

> so this is a real issue for us. On that volume a 400GB VDI consumes
> 800GB
> - 400GB for its base disk, and 400GB for the snapshot disk.

Is a root disk?
What's the template size, Have you shrunk the template before uploading to CloudStack? 
A shrunk VHD file has the size about space being used.

-Anthony




> -----Original Message-----
> From: James Kahn [mailto:jkahn@idea11.com.au]
> Sent: Thursday, August 23, 2012 3:47 AM
> To: cloudstack-users@incubator.apache.org
> Subject: CloudStack and XenServer 6.0.2 - stray snapshots on primary
> storage
> 
> Stray CloudStack generated snapshots on primary storage are causing
> significant storage use on our XenServer environment. Is this expected
> behaviour, a bug, or are we encountering an environmental issue? Is
> anybody else seeing this?
> 
> One particular storage volume has over 1TB in use, with 659GB allocated
> 
> so this is a real issue for us. On that volume a 400GB VDI consumes
> 800GB
> - 400GB for its base disk, and 400GB for the snapshot disk.
> 
> Pretty much every primary storage volume is affected. Snapshots are
> exported successfully to secondary storage.
> 
> Some details on our environment:
> CloudStack 3.0.1
> XenServer 6.0.2
> iSCSI primary storage (CloudStack managed)
> 
> The snapshots also seem to be recently current, as shown:
> 
> # xe vdi-list sr-uuid=1ddf05ad-133e-a275-90de-8b03fb69d114
> is-a-snapshot=true params=uuid,name-label,snapshot-time
> uuid ( RO)             : fb9210b9-25e5-46fd-a747-26e0dc536981
>        name-label ( RW):
> 034ef007-b6a5-40f0-81a0-6f59953a59eb_ROOT-1240_20120423023335
>     snapshot-time ( RO): 20120423T02:33:37Z
> 
> 
> uuid ( RO)             : ea5392b0-8921-46ca-b74f-c16aa8e78466
>        name-label ( RW): Template routing-1
>     snapshot-time ( RO): 20120404T05:10:49Z
> 
> 
> uuid ( RO)             : eba80a35-2acc-4228-905d-380a074135de
>        name-label ( RW):
> 511f0f27-d130-4bf3-801d-3c2248efcfe0_DATA-1229_20120822180201
>     snapshot-time ( RO): 20120822T18:02:04Z
> 
> 
> uuid ( RO)             : 420c397e-8828-4b80-88ff-1db141cc7d16
>        name-label ( RW): Template 98255702-1359-42ae-b635-ad7eacd09e5c
>     snapshot-time ( RO): 20120411T23:28:35Z
> 
> 
> uuid ( RO)             : b606c514-a042-4493-a0a7-07c7c5f66d3a
>        name-label ( RW):
> 511f0f27-d130-4bf3-801d-3c2248efcfe0_ROOT-1229_20120822180201
>     snapshot-time ( RO): 20120822T18:02:21Z
> 
> 
> uuid ( RO)             : 14a75d57-8e1b-4ee7-b1b8-d069362332e9
>        name-label ( RW): Template 5978eab4-166c-42f1-aeb6-a4d6bb8bb5f9
>     snapshot-time ( RO): 20120412T05:48:58Z
> 
> 
> uuid ( RO)             : 90559f54-e35a-48e3-9ce0-5e9d8b4e5587
>        name-label ( RW):
> ff484c2e-2b8c-4c73-9b54-da404cfa962e_ROOT-1232_20120822150201
>     snapshot-time ( RO): 20120822T15:02:04Z
> 
> 
> Any ideas?
> 
> Thanks,
> JK.
> 
> 
>