On Tue, 8 Sep 2009 17:11:25 -0400, Joel Wolpert <[email protected]> wrote:
>If I recall correctly there is a big hit (10-20% overhead) for the first 2 >systems in a sysplex when doing DB2 datasharing. After that the overhead >drops drastically. >For other sysplex implementations the overhead can be much less. > >Joel Wolpert >Performance and Capacity Planning consultant >WEBSITE: www.perfconsultant.com Good point. I assume your statement is related to DB2 CPU consumption only, not the entire system. I tend to live in my own little operating system world, so my numbers were just related to OS overhead. I was part of many parallel sysplex implementations in the past, but never have been at a shop "just before" and "just after" a DB2 datasharing implementation to compare numbers. I haven't looked at this aspect in a while, but I think the DB2 manuals may quote a similar number (10%). As it turns out, I think we will be implementing DB2 data sharing here for one of our environments that doesn't utilize it now. The access between 2 LPARs is currently DDF (formerly type 2 connector, now type 4 / DRDA to utilize zIIP) - so overall we expect this to be an improvement. When it was type 2, it was more clear on what the MIPS and dollar savings would be, but with zIIP thrown in the picture now, I'm not sure. Regardless, performance will be better for the LPAR that is not local today but the current DB2 "owning" LPAR will take that hit that you are referring to. Mark -- Mark Zelden Sr. Software and Systems Architect - z/OS Team Lead Zurich North America / Farmers Insurance Group - ZFUS G-ITO mailto:[email protected] z/OS Systems Programming expert at http://expertanswercenter.techtarget.com/ Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.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
