I changed the subject line... On Fri, 13 Mar 2009 14:33:42 +0100, R.S. <[email protected]> wrote:
>BTW: Why do you run HSC on each system? 1) History (SMC client / server didn't used to exist). It was also not recommended to switch to it in our environment when it did become available. We were having enough problems at the time with VSM (and not too long after with SL8500s) as it was. :-) 2) Less operational complexity. Any system can come down or up without losing access or having to startup / move a host HSC. That same benefit applies to an unexpected outage. I don't like sysplex failover scenarios that rely on only certain systems being able to handle the takeover. We have that today with CA-11 since it started using Datacom and it is nothing but headaches when we have change windows because operations has to be aware when certain systems can come down or they have to start a CA-11 MUF task on a different LPAR. It's much worse than HSC because Datacom only allows a single "shadow MUF" in addition to the "master". >BTW2: Such approach has serious limitation. AFAIR there is a limit of 16 >HSCs sharing CDS. Not to mention RESERVE contention for such many systems. The 16 system limit is not a problem. Our biggest HSCplex <grin> is 10 systems (2 of them have that many). We haven't looked at this in a few years, but I don't think there is any contention / performance problems even with the 10 systems sharing the CDS. I support the next time we upgrade releases I may look into it again, but the current environment is not a problem so in this case it is probably "if it ain't broke, don't fix it" since the alternative could be more complicated for operations. BTW, if the sharing scope is within a sysplex you can use CF structures for CDS data sharing. So while we are on this subject, is anyone else out there other than Radoslaw using an SMC client / server configuration in an all z/OS environment (I know there are) and have any comments? 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
