When we were tight on DASD, I used have to keep my one-pack rescue system and my second level maintenance system stored on tape. It slowed down the
maintenance cycles quite a bit. But now that we have some spare DASD, my maintenance system is online all the time, sometimes I even have two onli ne at the same time (Z51RES, Z53RES). And I no longer have a one-pack rescue system. The maintenance system is IPLable and has all my utilities for rescuing any of the production systems. It even has ZZSA so the z/OS peop le can edit a mangled SYS1.PARMLIB. /Tom Kern /U.S. Dept of Energy /301-903-2211 On Thu, 3 Sep 2009 08:57:24 -0500, Mike Walter <mike.wal...@hewitt.com> w rote: >Second level system disks allocated as an MDISK on real cylinders 1-end >has a lot of advantages. Especially for experienced VM customers. > >But it also keeps one from IPLing that sysres allocated as a MDISK >(beginning on real cyl 1) on the bare metal when things go bump in the >night. On that dark and stormy night one wants ANY type of VM system to >be IPLable to permit rapid recovery of the production 1st level system >(usually without backup tapes!). When that happens, that (540RES ?) >sysres beginning on real cylinder zero sure does look nice when it IPLs >from the HMC. > >Yes, we have an emergency 1-pack 3390-3 IPLable z/VM sysres DASD ... but >how many newbies do? No IBM doc that I recall describes creating a 1-pa ck >emergency IPL disk, nor the importance of creating it immediately after >fully completing the first z/VM installation for the first time (when on e >is most likely to make an inexperienced choice, taking down that only z/ VM >system. > >So, as a wise, famous lil' ol' IBM VM'er often says: "It depends." > >Mike Walter >Hewitt Associates >The opinions expressed herein are mine alone, not my employer's.
