clist19.html

Cheryl's List #19 - February 18, 1999

http://www.watsonwalker.com/archives.html

In this issue, I'll cover the following:

1. Cheryl Watson's TUNING Letter, 1998, No. 6 Summary
2. Important APARs
3. Good Web Site
4. SHARE in SF

1. Cheryl Watson's TUNING Letter, 1998, No. 6

The 1998, No. 6 TUNING Letter issue was mailed on February 11, 1999. The Management Issues section is included below to give you a sense of the scope and contents of the issue. The page numbers refer to pages in issue No. 6, of course. The TUNING Letter is a print-only product published six times a year, with an average of forty pages per issue. See our Web page for details!

Focus: Upgrading A Processor

I seem to get more questions about processor upgrades than any other topic. Part of this interest is due to the high acceptance of the very fast CMOS processors. Both IBM and Amdahl have seen higher than anticipated shipments of their CMOS machines and HDS is shipping new Skylines all the time. The Focus in this issue is on processor upgrades - how to size them, why you might not see the expected capacity, and how to avoid the most common problems after an upgrade. "Problems after an upgrade? Why would that happen?" you say? It's a matter of expectations versus observation. In three articles starting on page 14, I explain why the speed and capacity of a new processor can be quite hard to predict.

Important Warnings

This issue contains several important warnings for you:

MVS/SP 4 and ISPF V4 introduced an integrity exposure for library updates that still exists and is hurting some sites. Page 29 describes the problem with the View command and how to control it.

TCP/IP for OS/390 R5 was re-written and eliminates support for a function used by several ISVs (Independent Software Vendors). If you're planning to go to R5, you must check with your vendors (page 28).

One of the more important items in this issue is the notice about a WSC Flash W98044 (Positioning for Year 2000). IBM has provided a document that explains why multi-system sites that are planning to freeze operating system releases should stabilize on at least OS/390 R5 instead of R2 as many sites are currently doing (page 10).

You should never, ever, ever, place a production coupling facility in an LPAR that shares CPs with other LPARs. Page 28 describes some WSC flashes that help you understand the reasons behind this warning.

Many installations are seeing an increase of 10% to 30% in their programs after converting to Y2K. I've listed some ways to avoid the overhead on page 32.

Cheryl's Updates

In this section (page 28), I provide updates on some topics that I've previously discussed. In addition to some of the warnings above, I cover the following items.

The catalog CPU overhead problem is now documented in a single APAR.
IBM seems to have eliminated the discrepancy in COBOL packed decimal performance with their G5 (9672-Rx6) processors.
Workload manager's "small consumer" logic has frustrated some people - there's a description and status.
Web Server classification rules are incorrect in the WLM manual - there's an update from the WLM developers.

Elsewhere

Our Q&As on page 34 answer four very common questions: how to set LPAR weights; why fixed storage problems occur; when will WLM compatibility mode go away; and what is the real overhead of WLM goal mode. Our S/390 News provides good news on the following: tremendous performance benefits of using GRS Star; how to get a free cross-reference between MXG and CA-MICS files and variables; why some people are seeing overhead in hardware data compression; causes for CPU overhead during Y2K migrations; some feedback on further LE problems; a final solution to the OS/390 R4 JES2 $ACTIVATE problem; some nifty new Web sites; and several new books worth your notice on UNIX, Lotus Domino, and S/390. Many sites were shocked to hear of the CPU increases in CICS after LE implementation, but Bob Archambeault reports on five new IBM APARs that result in outstanding performance improvements for CICS and LE on page 36.

2. Important APARs

Eliot Swiger of Belk Stores Services agreed with my warning in this last newsletter about the TCP/IP and OS/390 R5 issues. His site had several problems with TCP/IP when going to R5. He recommended that you look at two information APARs, II11553 and II11180.

At the last SHARE, a few people complained about SDSF users being swapped out for a long time (seemingly forever) when trying to select a swapped out address space. Having heard of the query, Kathy Walsh and Gail Whistance, both of IBM, sent me a pointer to APAR PN91283 (closed 97/08), which deals with this common problem. According to the APAR, this applies to SDSF 1.6.0 and OS/390 R3 users.

3. Good Web Site

Have you ever wanted a cross-reference between CA-MICS and MXG files and variables? It's now available free online as a service by Nicus Software Inc. on their Web site at http://www.nicus.com. Nicus is well known for their products and consulting services in IT accounting and chargeback, capacity planning and performance management. The cross-reference is part of a Web section that helps people convert from CA-MICS to MXG and includes sample code and steps for conversion. The cross-reference itself, however, can be used to do a lookup either way (e.g., you have the MXG name and want to know which CA-MICS name it corresponds to).

I think this is a wonderful service that will be valuable to many installations. Don't miss some of the other goodies on their Web site, such as the free downloadable programs. One creates a comma separated variable (CSV) file from any SAS data member. Thank you, Nicus!

4. SHARE in SF

I'll be attending SHARE in San Francisco February 21-26 - see http://www.share.org. We won’t have a booth, but I’ll be giving two sessions:

2594

Cheryl’s WLM Quickstart Policy Update & Recommendations

2543 (Friday 9:30am) - Cheryl’s Hot Flashes

That’s all for now. Stay tuned!

Cheryl Watson

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