Setting primary server for MPIO Fail Over

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bjobie
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Joined: Mon May 06, 2013 5:31 pm

Mon May 06, 2013 5:40 pm

Hello,

We have a two node HA storage setup. One of the nodes has better hardware, so we prefer to have that as the primary node with the other node being just for backup/fail over.
MPIO.png
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It works well that if, for some reason, the primary node goes offline everything fails over to the standby node. My question is - is it possible to have it automatically switch back to the primary node when it comes back online?
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anton (staff)
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Mon May 06, 2013 5:45 pm

1) It's recommended to have ALUA configured in your case as primary server is expected to handle more of the workload.

2) It will fail back to your primary server if you'd properly configure the MPIO failback policy. See:

http://technet.microsoft.com/en-us/libr ... s.10).aspx

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Configure the MPIO Failback policy setting
If you use the Failover Only load-balancing policy setting, MPIO failback allows the configuration of a preferred I/O path to the storage, and allows automatic failback to be the preferred path if desired.
Consider the following scenario:
The computer that is running Windows Server 2008 R2 is configured by using MPIO and has two connections to storage, Path A and Path B.

Path A is configured as the active/optimized path, and is set as the preferred path.

Path B is configured as a standby path.

If Path A fails, Path B is used. If Path A recovers thereafter, Path A becomes the active path again, and Path B is set to standby again.
To configure the preferred path setting
Open Disk Management. To open Disk Management, on the Windows desktop, click Start; in the Start Search field, type diskmgmt.msc; and then, in the Programs list, click diskmgmt.
Right-click the disk for which you want to change the policy setting, and then click Properties.
On the MPIO tab, double-click the path that you want to designate as a preferred path.
Note
The setting only works with the Failover Only MPIO policy setting.
Select the Preferred check box, and then click OK.

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Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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bjobie
Posts: 3
Joined: Mon May 06, 2013 5:31 pm

Mon May 06, 2013 9:52 pm

Excellent. Setting the preferred path is what I was looking for. Now, I'm not sure how to enable ALUA. I remember it being an option when the servers were set up originally, but don't know how to get it done after they're in production. ??
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Anatoly (staff)
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Wed May 08, 2013 11:21 am

It is configuring in the target wizard from the StarWind side.
Best regards,
Anatoly Vilchinsky
Global Engineering and Support Manager
www.starwind.com
av@starwind.com
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