On Tue, 28 Aug 2007 09:12:15 -0400, John Eells <[EMAIL PROTECTED]> wrote:
>Rob Scott wrote: >> In the "old" days, issuing lots of vary operator commands could cause system problems - I am not sure if that has been fixed yet. ><snip> > >In z/OS R7, the code was changed to attach up to 32 subtasks to process >VARY OFFLINE commands in parallel. In z/OS R8, it was changed to do the >same for VARY ONLINE. We think this should have done a lot to relieve >contention for, e.g., SYSIEFSD Q4 (and if I remember right--always a >dangerous assumption--SYSIEFSD VARYDEV) while also processing VARYs for >a large number of devices in considerably less time. > The problems Rob was probably referring to had more to do with commands "backing up" and blowing away the commtask (console). The console restructure took care of that problem. Although obviously if you can do the commands in parallel, there is a much less chance of them "backing up". But the same (console) problem could happen in the "old days" from commands other than VARY also. Our "vary offline at IPL" program still has a .2 second delay built into it between commands because of the problem (changed from .5 second delay several years ago due to the speed of modern machines). I remember a similar issue under MVS/XA where MSTJCL00 had a region size coded of 32M and ran out of virtual storage. 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 and OS390 expert at http://searchDataCenter.com/ateExperts/ 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
