February 3, 2010
 |
- Welcome to Cheryl's List!
If you obtained this from someone else and would like your own FREE copy
of Cheryl's List in
the future, see the information at the end of this email.
- 2010.01.12 - DB2 9 for z/OS potential data corruption and DB2 crash after using the CATMAINT UPDATE SCHEMA SWITCH utility, which is new in DB2 9
- 2010.01.21 - z/OS Potential DB2 Data Inconsistencies Following a CF Failure
- Chapter 3 describes some z/OS tools, one of which is the IPLDATA block that contains timings during IPL. There is a link in the book to download a program to display that information. In order to get the most out of the Redbook, you should download the program now and run it.
- Chapter 4 describes the z/OS IPL sequence in more detail than you will find in any public documentation. If you want to understand the IPL logic, this is the place to come.
- Chapters 6 through 9 describe techniques to reduce the start up and shut down times for CICS, DB2, IMS, and WebSphere. You won't find this type of information in a single place, and the suggestions can greatly reduce the down times for these applications.
- You've probably seen separate Workload Manager recommendations for CICS, DB2, IMS, and WebSphere, but have you seen recommendations for when you run all of the subsystems at once? Try Chapter 5 and you will.
- 1. About Cheryl Watson’s Tuning
Letter 2009 No. 6
2. Important Notice About SHARE in Seattle
3. Latest Red Alert
4. Mean Time to Recovery Redbook
The forty-two page 2009 No. 6 Tuning Letter was emailed to paid subscribers on December 23nd. You may visit our Web site at www.watsonwalker.com to obtain subscription information. The following is our Management Summary page from that issue, talking about some of the contents of this latest Tuning Letter:
How to Influence
IBM
The SHARE organization is the largest
IBM user group that has as one of its goals the influencing of z/OS development.
They accomplish this by allowing SHARE members to create, discuss, and
vote on "requirements" to be sent to IBM. Within the core z/OS project
alone, IBM has implemented over half of the 1,000 requirements submitted
in the last few years. If your company is a member of SHARE, your employees
can help write and vote on these suggestions to IBM. Our article, starting
on page page 22, shows how they can do that. If your company isn't a SHARE
member, then I highly recommend that you consider it. For $500 a year (or
by just sending one person to one of the yearly conferences), a company
can become a member. This not only allows you to participate in requirements,
but also, more importantly, provides all of your employees access to all
of the past SHARE conference proceedings. We consider these proceedings
to be some of the best educational material available, and there is no
additional charge for any of it.
Understanding
Parmlib
The controls for z/OS reside in
one or more parmlib data sets, such as SYS1.PARMLIB. Three of the members
of parmlib (LOADxx, IEASYMxx, and IEASYSxx) determine how most of the other
parmlib members are used for each LPAR. A mistake made in any of these
members can be critical to how well (and whether) each LPAR is initialized.
In most installations, at least one senior systems programmer understands
the relationship between these members. But, unfortunately, this relationship
is often not well understood by the majority of new systems programmers
and performance analysts. Mistakes can result. Our Focus article (starting
on page 3) describes the IPL process from the operator IPLing a system
to the IPL process initializing and processing these three parmlib members.
Elsewhere in
this Issue
You'll find many other useful items
throughout this newsletter: New features of
ALLOCxx. • An update on capacity planning for Coupling Facility (CF) links.
• Many New Function APARs, including more DFSORT facilities and faster
SVC dumps. • Lots of warnings about invalid SMF data. • A great new Redbook
on modernizing your current batch applications.
2. Important Notice About SHARE in Seattle
I'm really looking forward to SHARE in Seattle (March 14-18), and I hope to see many of you there. In trying to reduce costs without increasing registration fees, SHARE has shortened from a 5-day event to a 4-day event (Monday through Thursday). But I'd like to issue a warning about Thursday. In the past, the conference finished on Friday at noon, and most people left for home in the afternoon. SHARE had scheduled some of the most highly attended z/OS sessions (e.g. Bit Bucket, z/OS Goody Bag, and my Hot Flashes) on Friday morning to encourage people to stay for the morning session. But those three sessions (and many more) are now scheduled for Thursday afternoon. And the MVS Free-For-All is scheduled for 6 on Thursday. So if you spend the money to travel to SHARE, it's very important for you to spend Thursday night in Seattle in order to gain the most from your trip. SHARE is still some of the best and least expensive training you'll find. For registration and more information, go to www.share.org.
3. Latest Red Alert
On January 12 and January 21, IBM
issued new Red Alerts. You can sign up to automatically receive Red Alerts
at http://www14.software.ibm.com/webapp/set2/sas/f/redAlerts/home.html.
After running the CATMAINT UPDATE SCHEMA SWITCH utility, object's DBDs were corrupted causing various overlay type ABENDs when accessing the row. This problem only affects databases that contain tables that have columns with user defined default values. As a preventative action, install the PTF for PK90557.
When a CF terminates the structures on the CF are physically deleted and duplex structures will fail over to the other instance of the structure and simplex structures will rebuild into a new instance of the structure. If the CF comes back up quickly after a CF failure, it is possible, and even likely, that the rebuilding structures will rebuild into the CF that just terminated and came back. While the new instances of the structures are being allocated, XCF may still be cleaning up for the prior instances of structures that were allocated in the CF before the CF Failure. As part of the cleanup XCF may incorrectly delete record data from the new instance of a lock structure.
The Redbook that I worked on in May
is now available in draft form - SG24-7816-00
- System z Mean Time to Recovery Best Practices. Even if I hadn't worked
on it, I would have told you that it's a fantastic book! I'll have more
to point out in our next Tuning Letter issue, but for now, I'd like to
point out four things to make you rush and get it:
Cheryl Watson
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