Checking the Actual Cache Status of The Sun Storage 3000 Array

Asset ID:	1-72-1002332.1
Update Date:	2010-11-15
Keywords:

Solution Type Problem Resolution Sure

Solution 1002332.1 : Checking the Actual Cache Status of The Sun Storage 3000 Array

Applies to:

Sun Storage 3310 SCSI Array
Sun Storage 3320 SCSI Array
Sun Storage 3510 FC Array
Sun Storage 3511 SATA Array
All Platforms

Symptoms

{SYMPTOM}
Symptoms

The Sun Storage 3000 arrays sccli versions 2.0 and below "show cache-parameters" command reports the following:

 * cache-parameters
mode: write-back
optimization: sequential
sync-period: disabled

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:



[Primary]       Alert
Force Controller Write-Through on Trigger Cause

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":


Tue Jan  4 10:35:48 2005        3510     - 3510D        Cache Status: Clean
WT

Changes

{CHANGE}

A bug was introduced in the sccli software for versions prior to 2.2.0.3. Upgrading to the latest available sccli software is the recommendation to avoid hitting this issue.

Cause

{CAUSE}

Please see Sun Bug ID 6219384. The 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
(currently 2.5).

Solution

Resolution

This issue was resolved with sccli 2.2 and later software, which has added the parameter:
"current-global-write-policy" which will indicate the actual cache mode. The cache mode
may have changed to "write-through" due to one of the triggers found in the 4.x firmware,
for example a controller failure.

If a controller failure occurs, we would get the following event logged :

Tue Jan  4 09:03:27 2005
[Primary]       Alert
Force Controller Write-Through on Trigger Cause

Now running the "show cache-parameters" command will display:


sccli> show cache
mode: write-back
optimization: sequential
sync-period: disabled
current-global-write-policy: write-through

The "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.

Internal Comments
Change History
Date: 2010-11-15
User Name: [email protected]
Action: Currency & Update

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