> Is a PDSE with a RECFM=VB weird? I hope not because I use that format > for my C/C++ source libraries that don't reside in the z/OS UNIX file > system.
Yes, that is weird. Check the archives for my woes with that format - both performance wise and corruption wise. In a large VB PDSE with many members, there is absolutely no caching from the PDSE address space(s), as that cache encompasses the full 4k page. And the cache is limited to ridiculously low values. So no effective directory caching last I looked. A 70.000 cyl PDSE with recfm=VB and about 10000 members in ISPF 3.4 takes 90 seconds to open, and the time is spent doing I/O to DASD (I/O response time between 4-6ms - I traced that). Basically one I/O is done per member, often more than one. And those large PDSEs are prone to (undetected) corruption - several times since 2004, when we started using them. Barbara ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
