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The cache mode displayed with  sccli "show cache-parameters"  command may not be accurate and reflect the current cache state of the array. This is only true for versions 2.0 and older of the sccli software.

Applies to:

Symptoms

"show cache-parameters" command in sccli versions 2.0 and below with Sun Storage 3000 Arrays reports the following:

The cache mode displayed as a result of the above command is not dynamic, meaning that if the cache mode changes, the "show cache-parameters" will continue to report the earlier mode.

The only way of finding the actual cache status was to look for the following message in the event log:

OR

From the telnet/serial interface, check the banner of the initial screen for the "WT" which indicates that the cache mode has turned to "Write Through":

Cause

sccli versions 2.0 and below did not have the parameter "current-global-write-policy" to display the current status of cache policy.
The reporting is improved since sccli version 2.2.0.3 which introduced new parameter "current-global-write-policy". Upgrading to the latest available sccli software (currently 2.5) is the recommendation to avoid hitting this issue.

This issue was covered under bug 6219384 (but we do not have the equivalent Oracle Bug). The sccli version that actually fixes the bug is unclear.

Upon testing, it was found that sccli 2.1.1 fixes this problem for SE3510, SE3310 and SE3511 however this wasn't fixed for SE3320.
sccli 2.2.0.3 fixes this for all minnow products. The recommended solution is to upgrade to the latest available sccli software version.

Solution

The cache status reporting is improved since sccli ver 2.2 and later software, which has the parameter: "current-global-write-policy" which will indicate the actual cache mode.
Now running the "show cache-parameters" command will display:

The cache mode may have changed to "write-through" due to one of the triggers found under "show auto-write-through-trigger"

For example, if a controller failure occurs, we would get the following event logged :

Thus the parameter "current-global-write-policy" will tell us the actual cache status which indicates that the array currently is running in write-through mode and action(s) need to be taken to address the root cause accordingly.

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