Jim, Does this file system need to be written to? If not you could make it read only and this would alleviate the problem as well. The only time it would need to be R/W is when you were applying maintenance.
Talk to me offline about other tricks you can play if the application is writing to this file system. ___________________________________________ Jim Petersen MVS - Lead Systems Engineer Home Depot Technology Center 1300 Park Center Drive, Austin, TX 78753 www.homedepot.com email:[EMAIL PROTECTED] 512-977-2615 direct 210-977-2930 fax 210-859-9887 cell phone -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Jim Marshall Sent: Tuesday, August 12, 2008 2:07 PM To: [email protected] Subject: Tivoli Workshop Scheduler "Eats Lunch" Resolution Working with IBM Level 2 or maybe 3, we now understand what is causing the excessive CPU time being used by the Distributed component of Tivoli Workload Scheduler. I will review the scenario: Running a IBM 2096-O02 (36MSU) and 2096-T03 (95MSU) machines in a Parallel Sysplex where TWS runs on the "O02" system (smaller of the two). TWS is scheduling work in the Parallel Sysplex and also there is a distributed component for scheduling for 3-4 Windows Servers. Historically it is interesting for TWS had its roots in an IBM product called OPC (Operator Control) which did z/OS and distributed scheduling using "Trackers". It worked very well using little CPU time. OPC morfed itself into Tivoli and became TWS for z/OS and IBM bought a company called Maestro which did distributed scheduling. The two products were merged and Trackers went away. It took IBM a few years to fully integrate the two products. This brings it down to the present and performance issues encountered. TWS for z/OS runs separately from other Started Task for distributed TWS called TWSE2E. TWSE2E was seen taking about 3 MSUs worth of the O02 when the system used to run around 28-29 MSUs max in a month. IBM researched the issue and came forth with the explanation which is not highlighted in any of the Tivoli manuals as far as we can read. The TWSE2E executes its programs in the O02's USS system and has files defined in a zFS file system. If indeed that zFS file system is not owned by the LPAR where TWS is running, all the I/O must go through XCF in the Parallel Sysplex; generating the extraordinary amounts of CPU time seen as being used by TWSE2E in that LPAR. The recommendation now is always have the zFS file system mounted to the LPAR where TWS is operating (otherwise TWSE2E will eat your lunch, dinner, etc). When we switched TWS's zFS file system back to the TWS LPAR, the CPU consumption dropped to almost nothing. I can understand the recommendation and now it places some considerations to ponder: 1. When a TWS LPAR is taken down the ownership of its zFS file system is automagically transferred to some other LPAR and it is not your choice which one (another interesting discussion could follow this line). So when the TWS LPAR is IPL'ed, operationally one must ensure the proper commands are issued to bring back ownership of TWS's zFS file system. 2. One can implement all of #1 in "Automation" if one is running some sort of automation package; a good case for getting one. 3. Keep in mind this is not a Parallel Sysplex problem but a zFS challenge. 4. I just have to wonder if all this is caused by I/O for TWSE2E having to go through XCF to get to the other LPAR where the zFS is owned, then why not the WAIT associated with I/O versus the heavy, heavy CPU load caused by this I/O (3-4 Windows Servers which get about 30-40 jobs per day)? Note: I just have to believe there is more to the story and it may not be a TWS problem but maybe TWS exploiting something in USS and zFS which is a bad design. POSTSCRIPT: Things are back using an acceptable amount of CPU and everyone is older and wiser. Jim P.S. Wonder how many other z/OS USS implementations are using excessive CPU because of the ownership of some zFS file system. Will be on the watch for something like it in the future. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
