IBM Support

Potential Loss of Access When Using Backend Storage Systems with Round Robin Multipathing

Flash (Alert)


Release V6.3.0 of SAN Volume Controller, Storwize V7000 and Storwize V7000 Unified introduced a new multipathing driver for most IBM storage systems and certain other storage controllers.

There is a small risk that a customer using this multipathing driver may experience I/O errors when recovering from communication issues with these storage controllers.


The Storage Systems which use the new Round Robin Multipathing drivers are documented in the Interoperability matrices here:

Note: The links provided are for SAN Volume Controller, but the round robin behaviour is identical on Storwize V7000 and Storwize V7000 Unified.

In the event of a communication issue with a storage controller that is utilising round robin multipathing, there is a small chance that the multipathing driver will not recover correctly, and this may lead to a managed disk group offline caused by an IO time-out (error code 1340) or node warmstarts.


This issue is resolved by APAR IC81757 in V6.3.0.4 and V6.4.0.3 for SVC and Storwize V7000.

This issue will be resolved in a future release of Storwize V7000 Unified.

Cross reference information
Segment Product Component Platform Version Edition
Disk Storage Systems IBM Storwize V7000 (2076) 6.4 IBM Storwize V7000 6.3, 6.4
Disk Storage Systems IBM Storwize V7000 Unified (2073) 1.3 IBM Storwize V7000 1.3

Document information

More support for: SAN Volume Controller

Version: 6.3, 6.4

Operating system(s): SAN Volume Controller

Reference #: S1004166

Modified date: 18 September 2012

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