Hi John, I should have included more caveats in that message; I didn't mean to imply that AIX performance is ALWAYS better than OS/390. You can certainly set up configurations where either OS/390 performs better, or where AIX performs better. And I am certainly not an AIX wizard, my background is primarily in OS/390 performance & storage management.
In many cases, as you said, people get better performance on TSM/AIX simply because they are running the AIX TSM server on a dedicated host and don't have to fight for resources. The AIX TCP/IP stack also performs much better than the TCP/IP stack on the earlier versions of OS/390; in every release of OS/390 that is getting better. And it appears to me that AIX has a shorter code path for doing I/O than OS/390. AIX also uses all the available free memory in the box for (in OS/390 terms) I/O buffers, and the I/O just flies, even though the AIX boxes don't have the back end I/O processor hardware that mainframes do. On the other hand, many OS/390 systems benefit from having a lot of I/O paths available where you can tune and spread the I/O around, where some people order AIX boxes with just one disk I/O bus (that's a MISTAKE!), so that you eventually will hit a dead end on throughput. Now those are all just BLAZING GENERALITIES, I know -- and I'm the first to tell you that the answer to all tuning and configuration questions is: IT DEPENDS!!! My intent was just to assure the original writer that she could move TSM off her OS/390 system to AIX without worrying about giving up performance. -----Original Message----- From: John Naylor [mailto:[EMAIL PROTECTED]] Sent: Friday, February 21, 2003 4:04 AM To: [EMAIL PROTECTED] Subject: AIX TSM better than OS390 TSM ? Wanda, You wrote :- <If you want to save mainframe disk and tape, your best bet would be to <move <to TSM on an AIX server (depending on the size of your clients, a WIn2K <server might do). You get the same great product, terrific performance <(as <an ex-mainframer I can tell you the performance on AIX is incredible - <wouldn't have believed it if I hadn't seen it myself), and NO <conversion <costs for your clients. You won't have to change ANYTHING on the <client end! So why is the performance on AIX so good, compared to the mainframe. Does TSM inherently run better on AIX, or is it because in many cases the AIX box will be dedicated to TSM, while OS390 TSM will usually be sharing with many other applications, and that it often does not get the resources it needs to run at optimum. We have both TSM's at our site and my perception of the usual applies here the AIX TSMs are dedicated, while I have to share a busy mainframe. John ********************************************************************** The information in this E-Mail is confidential and may be legally privileged. It may not represent the views of Scottish and Southern Energy plc. It is intended solely for the addressees. Access to this E-Mail by anyone else is unauthorised. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. Any unauthorised recipient should advise the sender immediately of the error in transmission. Scottish Hydro-Electric, Southern Electric, SWALEC and S+S are trading names of the Scottish and Southern Energy Group. **********************************************************************
