Hi Jack - For many, many years we had been iteratively testing the Erase-On-Scratch function to determine if the performance had improved over time (with new hardware/software releases) to determine if we could exploit EOS, but without getting too far into the weeds, the bottom line was that the overhead to implement EOS was too great--specifically the elapsed time. IBM did great work to dramatically improve the performance over time, but there was always going to be additional CPU and EXCP overhead--no way to avoid that. But we determined that the elapsed time it would take to scratch some of our larger data sets would negatively impact our batch window, so we never implemented it. Yes, you can select certain data sets instead of using "ALL", but that involves too much administrative overhead (and continuous updates as the environment changes) and at the end of the day, some of the largest data sets probably have the most sensitive data in them.
That said, you might want to check out IBM APAR OA61492 (and associated PE fixes). The DASD UNMAP function (or the non-IBM DASD equivalent) seems to perform "the same" Erase-On-Scratch function... but at the hardware level. We are using the EMC equivalent and it is working seamlessly--no z/OS side overhead at all and practically nothing at the DASD hardware level. Larre Shiller US Social Security Administration “The opinions expressed in this e-mail are mine personally and do not necessarily reflect the opinion of the US Social Security Administration or the US Government.” ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
