Battery availability for 5320 arrays with CSM100 disk trays dictates a choice be made about cache.

Asset ID:	1-79-2021196.1
Update Date:	2015-07-01
Keywords:

Solution Type Predictive Self-Healing Sure

Solution 2021196.1 : Battery availability for 5320 arrays with CSM100 disk trays dictates a choice be made about cache.

Applies to:

Sun Storage CSM100 Array - Version All Versions to All Versions [Release All Releases]
Sun Storage 5320 NAS Appliance - Version All Versions to All Versions [Release All Releases]
Sun Storage 5320 NAS Cluster - Version All Versions to All Versions [Release All Releases]
Sun Storage 5310 NAS Appliance - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

Purpose

The 5300 NAS Controller Unit, A.K.A. CSM100, includes a battery backup to maintain the integrity of the controller’s data cache for up to 72 hours in the event of power loss to both power supplies.
Due to Oracle no longer being able to provide replacement batteries for the CSM100 disk trays, customers need to make a decision regarding how to proceed.

NAS systems with a Gateway license may not have effected storage attached and thus not be effected.

Scope

To determine if your storage is effected, send yourself a diagnostic e-mail from the NAS.

Sun StorageTek NAS OS Administration Guide, Sending a Diagnostic Email Message

In the included Diag.txt file you can see the Model name of the disk controller.
Model name 2882 indicates an effected CSM100 controller.
Model name 3992 indicated an uneffected CSM200 controller.

e.g.:

* Hardware Information
--------------------

Serial Number : <serial_number>
Memory Size   : 3968 MB

* Disk Sub-System Information
---------------------------

- Controllers Information
    -----------------------
    Number of Controllers : 2

    ~ Controller : 0

      Firmware Version : 06.19.25.16
      Model Name       : 2882
...

Details

If you have an effected disk tray, the first option is to do nothing.
In this case, once the battery fails due to age or fault, write cache will be disabled automatically.
Write performance will be impacted but the extent depends on your specific usage of the NAS.

The second option is to, upon battery failure, enable "cache without batteries".
If you wish to enable this option, please open a service request with Oracle support.
This setting will retain write performance but, in the case of loss of power to the CSM100, any data written to cache, that has not been flushed, will be lost.
The loss of data in the cache will likely require a fsck of the volume which may take an extensive amount of time depending on the volume size. During the fsck the effected volume will be unavilable.
The loss of data in cache may also result in unrecoverable data corruption.
If this is encountered please open a service request for assistance.

Performing and understanding the fsck procedure on the SunStorageTek[TM] 5000 Series NAS arrays to recover from a filesystem crash(Doc ID 1006816.1)

Reference:
On the rear of the CSM100 controller unit under the serial port is the "Cache Active" LED which provides an indication of the cache status.
Steady green indicates that data is in the cache.
Off indicates that all data has been written to disk and the cache is empty.

se5320-b > load lsi_menu
se5320-b > lsi_menu
Found 1 Array
        *************************************************
        *             SUN Microsystems                  *
        *           Engenio Raid Utility                *
        *               Version 1.3                     *
        *************************************************
         1. Array Menu
         2. Volume Group Menu
         3. Volume Menu
         4. Disk Drive Menu
         5. Support Menu
         6. Exit
Selection: [1 - 6] 3

         ******* Volume Menu *******
         1. Show Non-Optimal Volumes
         2. Show All Volumes (short)
         3. Show All Volumes (long)
         4. Show one Volume
         5. Show Lun Mapping
         6. Modify Volume Cache Setting
         7. Modify Volume Media Scan Setting
         8. Exit
Selection: [1 - 8] 6
Array Number: 1
Enter Volume/LUN ID: <CR to abort>: 1
                                               ----------------CACHE--------------
       VOLUME                      VOL --LUN-- --READ- -WRITE-          READ WRITE
        NAME        STAT GB RAID GRP ID SSID ENA ACT ENA ACT MIR CWOB MULT FLSH
-----------------ARRAY 1----------------------------------------------------------
102035_17_Oct_2007   OPT 1952   5   2   1   1   1   1   1   0   1   0    1    8
----------------------------------------------------------------------------------

   Volume name: 102035_17_Oct_2007
      Volume ID: 60:0A:0B:80:00:11:FD:B8:00:00:0D:BF:47:15:CC:BC
      Subsystem ID (SSID): 1
      Status: OPT
      Action: 1
      Tray loss protection: No
      Preferred owner: Controller in slot A
      Current owner: Controller in slot A
      Capacity: 1952 GB
      RAID level: 5
      Segment size: 64 KB
      Associated volume group: 2
      Read cache: Enabled
      Read cache active: Yes
      Write cache: Enabled
      Write cache active: No
      Flush write cache after (in seconds): 8
      Cache read ahead multiplier: 1
      Enable background media scan: Enabled
      Media scan with redundancy check: Disabled

***** 0 Missing Volume(s):

        Read Cache Enabled [enable/disable] ? e
        Read-Ahead Multiplier [1], new value [1-100] : 1
        Write Cache Enabled [enable/disable] ? e
        Flush Write Cache after 8 secs, new value [0 - 15]): 8
        Write Cache without Battery Disabled [enable/disable] ? e
        Mirror Cache Enabled [enable/disable] ? e

        *** CACHE SETTING ***           CURRENT     NEW ***
        ---------------------------------------------------
        Read Cache:                     Enable    Enable
        Write Cache:                    Enable    Enable
        Write Cache without Battery:    Disable   Enable
        Mirror Cache:                   Enable    Enable
        Cache Read Ahead Multiplier:      1         1
        Flush Write Cache after (secs):   8         8

        Are you sure you want to make the change [y/n] ? y
        **** Volume Cache Parameters were set successfully.

         ******* Volume Menu *******
         1. Show Non-Optimal Volumes
         2. Show All Volumes (short)
         3. Show All Volumes (long)
         4. Show one Volume
         5. Show Lun Mapping
         6. Modify Volume Cache Setting
         7. Modify Volume Media Scan Setting
         8. Exit
Selection: [1 - 8] 8
        *************************************************
        *             SUN Microsystems                  *
        *           Engenio Raid Utility                *
        *               Version 1.3                     *
        *************************************************
         1. Array Menu
         2. Volume Group Menu
         3. Volume Menu
         4. Disk Drive Menu
         5. Support Menu
         6. Exit
Selection: [1 - 6] 6
se5320-b > unload lsi_menu
Unloading lsi_menu module ver 1.3...
se5320-b >

References

<NOTE:1006816.1> - Performing and understanding the fsck procedure on the SunStorageTek[TM] 5000 Series NAS arrays to recover from a filesystem crash

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