Potential Loss of Access When Using Backend Storage Systems with Round Robin Multipathing
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:
- V6.3 Supported Hardware List, Device Driver, Firmware and Recommended Software Levels for SAN Volume Controller
- V6.4 Supported Hardware List, Device Driver, Firmware and Recommended Software Levels for SAN Volume Controller
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 V126.96.36.199 and V188.8.131.52 for SVC and Storwize V7000.
This issue will be resolved in a future release of Storwize V7000 Unified.
|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|