Topic Last Modified: 2007-07-25

The Microsoft Exchange Analyzer Tool reads the following registry entry to determine the EMC PowerPath version installed on each node in the cluster:

HKEY_LOCAL_MACHINE\SOFTWARE\EMC\PowerPath\Version

If the Exchange Analyzer finds that the value of the second or subsequent node in the Exchange cluster differs for Version, from the value for Version on the first node in the Exchange cluster, an error is displayed.

This error indicates that the nodes in this Exchange cluster are not running the same level of EMC PowerPath driver. As a best practice, we recommend that all nodes in an Exchange cluster run the same level of EMC PowerPath driver.

EMC PowerPath is multipath I/O (MPIO) software. Multipathing provides for high availability data access by allowing a host to have up to 32 paths to access an external storage device, which facilitates failover and load balancing. Multipathing is not a feature of the operating system, but is supported through the MPIO Driver Development Kit (DDK), which provides a means for storage vendors to create inter-operable multipathing solutions.

When MPIO software is run, Microsoft Windows detects only a single drive while the MPIO software manages the multiple connections to various storage devices. If the MPIO driver is mismatched between different nodes of the cluster, it could lead to cluster failover problems.

To resolve this problem, you must upgrade all nodes to the same EMC PowerPath driver version.

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