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Fede_pg
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EQL + Hyper-V 2012 + DPM 2012: unable to create some snapshots

Hi, I've a EQL (now running 7.1.4 fw) with a four nodes Hyper-V 2012 cluster.

4.7.0 HIT are installed on these servers and the cluster is backed up using DPM 2012 (with EQL HW provider). The vms run only Windows Server 2008 R2 or Windows 2012 as guest OS.

The problem is that some virtual machines are being correctly backed up by DPM: the backup starts, the Hyper-V host creates a snapshot that I can see in the EQL Group Manager and then the snapshot is deleted when the backup job ends.

Unluckily, other vms can't be backed up. When the backup job starts, no snapshot is being created and on the Hyper-V where the vm runs I can see only some VSS errors in the event log. The error code provided means that the storage array refuses to create a snapshot due to a provider veto. Then the backup fails.

I don't know where the problem could be: the "bad" vms reside on the same host as the "good" ones and even a live migration doesn't solve the problem. Maybe it's not a host-related problem... . On some "bad" vms MSSQL is installed, but on other "bad" vms is not; on the other hand, SQL is installed on some "good" vms.


So far I tried to reboot the vms. the hosts and the DPM too, but without success, so I can exclude a transient VSS error. I tried to upgrade the EQL fw from 7.0.4 to 7.1.4, but again no success.

I found a post on Technet Forums where the solution seems to be to stop the EqlASMAgent [EqualLogic Auto-Snapshot Manager Agent] on the hosts. Could be this a viable solution?

I don't know how to troubleshoot this issue, any idea?

Thanks in advance.

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4 Replies

RE: EQL + Hyper-V 2012 + DPM 2012: unable to create some snapshots

Hello,

First thing if you want to keep using the H/W provider that comes with HIT/ME is to upgrade to HIT/ME 4.7.1.

However, MS has phased out H/W snapshot support in SP3 for DPM 2012 anyways.

•DPM Backups today need Volume snapshot to get the stable copy of Application

• DPM now with Windows Server 2012 R2 can use VM snapshot to Backup instead of volume snapshot

• Volume Snapshot is avoided using Dummy VSS provider (DPM Null Provider)

• HyperV has made changes to give DPM and App consistent VM snapshot.

• Backups are done from Live Volume

• Hardware or software provider are not necessary anymore as DPM does not need volume snapshot.

Only Applicable to HyperV over Windows Server 2012 R2

• Prereq - support.microsoft.com/.../2919355

support.microsoft.com/.../2919355

• Used only for CSV volume and Remote SMB. Not used for NTFS, REFS etc.

• Installed along with agent as separate service (VssNullProvider)

• Production Server Needs Reboot after patch installation before Null provider can work.

• “Vssadmin list providers” can be used to confirm the installation

VSS Provider priority in DPM

• Null Provider (default, can be disabled using Regkey)

• Software provider (if forced using Regkey)

• Default Provider (can be software or hardware)

To disable Null provider (on production server)

reg add "HKLM\Software\Microsoft\Microsoft Data Protection Manager\Agent" /v UseNullProvider /t REG_DWORD /d 0 /f

Regards,

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Fede_pg
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RE: EQL + Hyper-V 2012 + DPM 2012: unable to create some snapshots

First of all, thanks for your answer, you're always helpful!

Currently I'm running only 2012 products, not R2: so I have Windows 2012 (not R2) as host and guest OS and DPM 2012 SP1 (again not R2).

Does this apply to Win 2012/DPM 2012 too?

Provided that I'm not using ASM, could stopping the service lead to problems?

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RE: EQL + Hyper-V 2012 + DPM 2012: unable to create some snapshots

You can try that.   Or unregister the EQL HW provider is another option.

Solution Title HOWTO: Temporarily disable the EqualLogic VSS provider?

Solution Details Under some circumstances, you may need to disable the EqualLogic VSS hardware provider module, but be able to re-enable it later.

Please note that the content of this solution is not officially documented or supported. This has been observed to work in the past, but is not guaranteed to be stable or functional in the future. Until this is documented, we should not provide it to customers.

This can be done with the "eqlvss" command under Windows:

C:\Program Files\EqualLogic\bin>eqlvss /unregserver

You can confirm it has been removed with the following command:

C:\Program Files\EqualLogic\bin>vssadmin list providers

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool

(C) Copyright 2001 Microsoft Corp.

Provider name: 'Microsoft Software Shadow Copy provider 1.0'

Provider type: System

Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}

Version: 1.0.0.7

To add it, do the following:

C:\Program Files\EqualLogic\bin>eqlvss /regserver

C:\Program Files\EqualLogic\bin>vssadmin list providers

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool

(C) Copyright 2001 Microsoft Corp.

Provider name: 'Microsoft Software Shadow Copy provider 1.0'

Provider type: System

Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}

Version: 1.0.0.7

Provider name: 'DELL EqualLogic VSS HW Provider'

Provider type: Hardware

Provider Id: {d4689bdf-7b60-4f6e-9afb-2d13c01b12ea}

Version: 3.1.1.0

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Fede_pg
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RE: EQL + Hyper-V 2012 + DPM 2012: unable to create some snapshots

Hello, after further investigations, the problem seems to be DPM-related (corrupted filter bitmaps), so the EQL is running fine.

Thanks again for your help.

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