1. Highlights of Cheryl Watson’s TUNING Letter 2007 No. 2
2. Potential System z9 Hardware Problem
3. Corrections to Cheryl Watson’s TUNING Letter 2007 No. 2
4. z/OS Training
5. The zNextGen Project
1. Highlights of Cheryl Watson’s TUNING Letter 2007 No. 2
The fifty-one page 2007 No. 2 TUNING Letter was emailed to subscribers on April 26, 2007. Single issues may be obtained for $155 each from our Web site at http://www.watsonwalker.com. The following is a summary of just some of the contents of this latest TUNING Letter:
Rules of Thumb
Anyone who has ever done computer performance measurement knows about Rules of Thumb (ROTs). These make it easy to quickly evaluate a measurement value and determine if you are having a performance problem. Back when things were less complicated, you could establish a ROT and have it apply universally to just about any organization. Those who spent their time doing performance analysis would establish and validate new ROTs, and those attending performance conferences would return with new ROTs to apply to their performance data. But are ROTs still valid in today’s complex and varied environments? Our opinions may surprise you, and you can read them in the Rotting ROTs article on page 36.
SHARE and Hot Flashes
Although we mentioned SHARE briefly in our last issue, this issue contains our full SHARE Trip Report, starting on page 15. We provide some pointers to useful tools that we learned about during the week, describe some excellent sessions designed to teach z/OS basics, and pass along some important LE (Language Environment) maintenance. In a related topic, ourCheryl’s Hot Flashes #17 article on page 25 provides the results from our survey questions, passes along some useful tips, and highlights other gems we uncovered during the conference.
User Experiences
Please see page 29 to read about the latest additions to our user experiences collection. There you will find a tuning tip that may improve zFS performance dramatically, and some resources that will help your tuning efforts in a uniprocessor environment. You can also read about some early experiences with the zIIP specialty processor.
Elsewhere in this Issue
You will find our usual APAR recommendations starting on page 4 of this issue. We mention some New Function APARs that add new capabilities, plus some Interesting APARs that help you avoid performance problems and outages. • In our Nuggets from the Forums section on page 8, you can read about some unusual DFSMSdss behavior that could lead to data loss if you also use other backup products. • There are many useful items in our What’s New? section that starts on page 42. There are new versions of CICS and DB2 that have been announced. Enhancements have been made to the System z processors. There is a new RMF option that allows you to analyze your RMF data with a Web browser. Finally, there is an updated flash and a new APAR that makes some changes designed to reduce SRM overhead on faster processors.
2. Potential System z9 Hardware Problem
Reader Lawrence Jermyn alerted us to a potential microcode problem that could affect System z processors, both model 2094 (z9 Enterprise Class) and model 2096 (z9 Business Class). This is based on IBM z9 HIPER notice 041807B dated April 19, 2007. The potential exposure applies to all customers running these processors at the Driver-63 level.
Here are more details about the problem as taken from the notice:
We have uncovered a very narrow timing window that, if encountered, could result in a system outage condition. Although we feel that this window is very small, we have made the following MCLs HIPER due to the system impact that may occur.
DAL5 Driver 63 bundle 39
DAL6 Driver 63 bundle 36a
DAL7 Driver 63 bundle 33a (21 April)
DAL8 Driver 63 bundle 33a (28 April)
This problem may occur with the de-configure of any processor type (CP, ICF, IFL, zAAP, zIIP) resulting in a LPAR disable wait 300611 (unresponsive physical processor) generating refcode: 20390311 00000004 00000000. This window is more likely to occur when many processors are de-configured at the same time.
HIPER MCLs have been released in MCL Bundle #40 to address potential System outage events.
You might want to investigate these corrections if you are exposed to this problem. Thanks to Lawrence for bringing this is our attention.
3. Corrections to Cheryl Watson’s TUNING Letter 2007 No. 2
Shortly after our latest TUNING Letter was published, we got an email fromBruce Christopher of HSBC. He pointed out that one of the DB2 fixes we mentioned in one of the SHARE articles seemed to be incorrect.
Actually, when we originally mentioned the fix as part of our Cheryl’s Hot Flashes #17 session, we listed the correct APAR number of PK33403. But when we expanded upon this material in the TUNING Letter (at the top of page 28), we inadvertently listed the APAR as having the incorrect name PK33404.
We will make this correction to the permanent copy of this issue before it is placed on the 2007 DVD in early 2008. Thanks to Bruce for bringing this error to our attention.
4. z/OS Training
This item was mentioned in our latest TUNING Letter, but we thought it was important enough that we should also share it with the readers of this list. We receive lots of questions about where to get good z/OS training. Many organizations that used to do training are no longer providing it, and some of the training that is available is either not valuable or is too expensive. It seems that training budgets have become the frequent victims of budget cuts, so many workers are on their own when it comes to learning what they need to know.
One of the things we noticed at the most recent SHARE is that more and more of the MVS projects are offering sessions related to z/OS basics. This is somewhat of a departure for SHARE, which is often viewed as a user group for only the most experienced z/OS professionals. This is a good trend, but more people need to know about it so that they can change their perception of the conference.
A week attending SHARE can provide the same type of basic training that used to be available in classes, and the cost is less. You can use this training for people who are completely new to z/OS, or for those who are moving to different jobs within the organization (e.g. an application developer moving into systems programming or a sysprog moving into performance and capacity).
But what if you don’t even have the budget to send one person to SHARE? Although copies of the presentation handouts are not as valuable as participating in the real session, they are valuable to those who need the information. You can download many of these great session handouts, even if you couldn’t make it to the meeting.
Go to the SHARE Web site (http://www.share.org), and click on the link ‘Tampa Proceedings Available’. This will take you to the Proceedings area, where you can search in one of several ways. We suggest looking for sessions with numbers 2000-3999. At least for the sessions presented by the MVS Program, most of the session titles will have the prefix ‘z/OS Basics’. Although there are many good sessions here, we recommend you start with these three:
2891 – z/OS Basics: A z/OS Walking Tour through MVS Concepts and Facilities – Part 1 of 3
2892 – z/OS Basics: A z/OS Walking Tour through MVS Concepts and Facilities – Part 2 of 3
2893 – z/OS Basics: A z/OS Walking Tour through MVS Concepts and Facilities – Part 3 of 3
These were given by Bob Rogers of IBM, who is not only an entertaining speaker, but is one of the most knowledgeable people about the internals of z/OS. The best part is that you don’t even need to have a SHARE membership to access the site and download any of the available presentations.
If you are planning to attend SHARE as a new user, then be sure to arrive on Saturday in order to attend Bob’s sessions, which will be given on the Sunday of SHARE in San Diego.
5. The zNextGen Project
Much of the SHARE emphasis on z/OS basics has come about because of a fairly new project within the MVS Program named zNextGen. The goal of zNextGen is to make training available to those who are new to the z/OS platform. Many of the participants are young and just working their first jobs. There are others who are more mature, but who are new to z/OS because of a change in job assignments. If you have those in your company who are in these two categories, please alert them to this project, and pass the word to your management that SHARE is also a great vehicle for inexpensive z/OS training.
You can also learn more about zNextGen from the SHARE Web site (see previous item for the link). From the main page, select ‘Volunteer Center’, and then ‘Projects/Programs’. Scroll down the list until you find zNextGen (the last project in the MVS Program), then click on that link. You can learn about what the project is doing, and find links to other resources for z/OS novices. Even if you can’t attend SHARE, you can join the project for free and with no obligation. This is a great resource for the z/OS community. We fully support it, and hope that you will too.
Stay Tuned!