FS System: Non-Optimized Access Observed When Only One Path/Controller Available.

Asset ID:	1-72-2219453.1
Update Date:	2018-01-03
Keywords:

Solution Type Problem Resolution Sure

Solution 2219453.1 : FS System: Non-Optimized Access Observed When Only One Path/Controller Available.

Applies to:

Oracle FS1-2 Flash Storage System - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

Symptoms

Non-Optimized Accesses (NOAs) observed yet both Controllers are operational.

Changes

A failure in the SAN fabric external of the FS1-2 has likely occurred.

Cause

When both Controllers are operational/normal but there is a failed SAN path to one of them, NOAs are generated for any IO attempting to use the failed path. The FS1-2 will then change the ownership of any affected LUNs to the Controller with the working path. After a period of time, if no further IO is processed to those LUNs, the FS1-2 will change the ownership back to the assigned Controller even though the failed path still exists. This process is known as re-homing. Subsequent IO will repeat the process and generate more NOAs.

Example: a SAN switch connected to Controller-01 is disabled/failed. All LUNs will now be accessible via Controller-02 as there is no SAN path to Controller-01. LUNs that were previously assigned to Controller-01 may record NOAs and may attempt to re-home back to Controller-01 even though there is no SAN path available.

Solution

Enabling/fixing the SAN switch restored the SAN path to Controller-01 and no further NOAs or path transitions occur.

Resolution to this issue is contained within firmware 6.2.12 and higher.

References

<BUG:25265020> - LUN OWNERSHIP MOVES BACK TO ASSIGNED CONTROLLER EVEN THOUGH IT HAS NO UP PORTS

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