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Checking Cache Battery Status Without STRSST
Published: September 28, 2011
Hey, Joe:
Concerning your article about debunking cache battery rumors, did you know that there's another way to see cache battery information without going into System Service Tools (STRSST)? IBM is offering a new program called QSMBTTCC that allows you to display cache battery status from the command line. It's enabled by PTFs.
--Steve
As a refresher, IBM uses batteries in its disk controllers to provide caching for its disk drives. The batteries have a useful life of about 2.75 to 3 years and the system will start sending warning messages to change your batteries when your controller cache batteries are older than about 2.33 years. When one of these batteries dies, it may not cause a disk drive failure, but it will disable disk caching for the disk array the controller manages, and that will have a significant impact on hard drive performance.
The short version of all this is that it's wise to replace your disk cache batteries before they run down.
Generally, disk cache batteries are hot swappable, meaning that they can be replaced while your system is up and running. However, depending on your machine type, one of the batteries may be controlling a disk array inside the system CPU and the system must be taken down to replace that battery.
Historically, the operating system sends battery status warning messages to the system history logs and the QSYSOPR message queue. The problem with this approach is that it relies on you reactively catching the message and then arranging for cache battery replacement before the batteries run down. You can check battery status on your own, but that involves running through a number of System Service Tools (STRSST) options, which are somewhat kludgy to remember and run.
As Steve mentioned, IBM delivered a green screen method last year for cache battery checking by adding a PTF to i OS operating systems V5R4Mx, V6R1Mx, and V7R1Mx. This PTF delivers a new operating system program called QSMBTTCC, and can be run with the following Call Program (CALL) command.
CALL PGM(QSYS/QSMBTTCC)
Once the program is called, it displays and prints a report containing information on partition resources that contain cache batteries and the expiration date of each set of cache batteries. This information includes the following items as shown on the sample report at the end of this tip.
- The name of each system resource containing a cache battery.
- The serial number of each cache resource.
- The type and model number of each resource.
- The frame ID and card position where each of the resources is installed in your rack.
- Battery pack information, such as whether the resource contains a concurrently maintainable battery pack, what the estimated time is (in days) until the system starts issuing battery change warnings, and what the estimated time is (in days) until the battery pack might fail.
The trick with reading battery cache information is to change the batteries within a reasonable amount of time after you receive your first battery warning message, but well before you exceed the estimated time of error (when the batteries are scheduled to exceed their battery life). Remember that these times are only estimates. Your actual battery life may be longer or shorter than the number of days listed. The actual number of days until battery failure will depend on machine usage and a number of other variables affecting battery life. To avoid unexpected failure, it's wise to replace your cache batteries not too long after you receive the first battery warning message.
Your partition needs a special PTF to enable QSMBTTCC. Here are the PTF numbers that need to be loaded on your system to use QSMBTTCC.
For i5/OS V5R4Mx, load and apply PTF SI40403.
For i OS V6R1Mx, load and apply PTF SI40404, which is also available in cumulative PTF level C1102610 and above.
For i OS V7.1, load and apply PTF SI40406, which is also available in cumulative level PTF C1116710 and above.
Each PTF can be applied immediately or on a delayed basis.
Special thanks to Steven Segars for providing me information for this tip.
HTH
--Joe
Sample QSMBTTC output
RUNNING MACRO: BATTERYINFO -LIST -ALL
***LIST OF ALL RESOURCES THAT HAVE CACHE***
CONCURRENTLY CAN BE
RESOURCE SERIAL TYPE FRAME CARD MAINTAINABLE SAFELY
NAME NUMBER MODEL ID POSITION BATTERY PACK REPLACED
DC01 YL10P1057198 2BE1-001 3C00 C13 NO NO
DC04 YL10D1112023 575C-001 3C03 C2 YES NO
DC05 YL10D1096007 575C-001 3C02 C2 YES NO
DC06 YL10D1096015 575C-001 3C03 C5 YES NO
DC07 YL10P1080273 2BD9-001 3C00 C19 NO NO
DC08 YL10D1096007 572F-001 3C02 C1 YES NO
DC09 YL10D1112023 572F-001 3C03 C1 YES NO
DC10 YL10D1096015 572F-001 3C03 C4 YES NO
RUNNING MACRO: BATTERYINFO -LIST -WARN
***LIST OF ALL RESOURCES THAT HAVE CACHE
WITH THE ESTIMATED TIME TO WARNING IN DAYS***
EST. TIME EST. TIME
RESOURCE SERIAL TYPE FRAME CARD TO WARNING TO ERROR
NAME NUMBER MODEL ID POSITION (IN DAYS) (IN DAYS)
DC01 YL10P1057198 2BE1-001 3C00 C13 844 934
DC04 YL10D1112023 575C-001 3C03 C2 848 939
DC05 YL10D1096007 575C-001 3C02 C2 848 939
DC06 YL10D1096015 575C-001 3C03 C5 844 934
DC07 YL10P1080273 2BD9-001 3C00 C19 844 934
DC08 YL10D1096007 572F-001 3C02 C1 844 934
DC09 YL10D1112023 572F-001 3C03 C1 844 934
DC10 YL10D1096015 572F-001 3C03 C4 844 934
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