IF you end up paging heavily, THEN you want many volumes AND you want the volumes on separate RAID arrays as possible.
After that...my guess is if you have, say, 4-6 mod-3s per array, it might be time to move to less mod-9s. But if you are really in that much paging, add more memory. On a z10 it is much less expensive. On the other boxes, look at the used market. Of course if you have sufficient disk space to waste, use mod-9s and add more when they are 10-15% full. (Some shops make stupid IMHO rules like everything must be mod-9s, but there are a limited number of addresses in the dasd subsystem, and disk drives can be very large). Tom Duerbusch THD Consulting >>> "Bauer, Bobby (NIH/CIT) [E]" <[EMAIL PROTECTED]> 12/10/2008 10:09 AM >>> I got a great Christmas present! 8G dedicated to our new z/VM and zLinux pilot and new ficon attached DASD (9990V) to replace the escon DASD. The new DASD has both mod3 and mod9. As an old MVS dinosaur I'd create many different paging volumes on smaller disk (mod3) but there is some pressure to use the mod9's. It is a pilot so I have no idea what our load is going to look like. Obviously my mileage may vary but what is in use out there? Any thoughts, good or bad, about a mod9 for paging other than the possibility of contention? Thanks Bobby Bauer Center for Information Technology National Institutes of Health Bethesda, MD 20892-5628 301-594-7474
