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A disk may not come online if only non-optimized paths are available on Windows Server 2008 and Server 2008 R2

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Symptoms

Consider the following scenario:

In an MPIO/ALUA configuration on Windows Server 2008 and Server 2008 R2 where only non-optimized paths are available, a disk may not come online.

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Cause

This occurs because the default MPIO policy for ALUA capable controllers when using the Microsoft DSM is Round Robin with Subset (RRwS), and this policy does not allow a disk to come online without an optimized path being available.

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Resolution

If you have a configuration where you need to function with only non-optimized paths available, use one of the following MPIO policies:

·         Least Queue Depth

·         Failover Only

·         Weighted Paths

·         Least Blocks

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More Information

To change the default policy on Windows Server 2008 R2, use mpclaim.exe as documented in the following TechNet articles:

http://technet.microsoft.com/en-us/library/cc725907.aspx

http://technet.microsoft.com/en-us/library/ee619743(WS.10).aspx

For Windows Server 2008 you need to use a script such as the one referenced in the following post, because the version of mpclaim.exe for Windows Server 2008 does not support the commands necessary.

http://blogs.msdn.com/b/san/archive/2008/12/12/scripting-example_3a00_-how-to-set-the-mpio-lb-policy.aspx

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Keywords: kb

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Article Info
Article ID : 2653382
Revision : 1
Created on : 1/7/2017
Published on : 12/9/2011
Exists online : False
Views : 254