We have device count reduction on our wish list. Unfortunately we know of no way to accomplish that without taking (multiple) application outages to consolidate data on fewer larger volumes. High impact and high risk with the benefit going mainly to infrastructure care-and-feeders. Our stated goal of rolling-IPLs whenever possible would be severely compromised.
. . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-543-6132 Office ⇐=== NEW [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Ed Jaffe Sent: Friday, January 05, 2018 2:12 PM To: [email protected] Subject: (External):Re: Accessing 65536 devices On 1/5/2018 3:52 AM, John Eells wrote: > Jesse 1 Robinson wrote: >> We would like to be able to access >65535 device addresses (UCBs) >> from a single LPAR via a single IODF. The need is for bringing a new >> DASD subsystem online while retaining the old subsystem until all >> volumes can be copied across. We currently have spare UCBs available, >> but not enough to have all old and new devices online at the same >> time. Is this possible? > > You can have a maximum of 65,280* devices (not quite 64K) in > Subchannel Set 0. There are some things that can be accessed via > other SCSs, but IIRC the exceptions don't allow you to have more than > 65,280 primary devices online concurrently. That includes all > devices, of course, including networking, tape, consoles, and such. Skip, you might consider standardizing on larger capacity devices where it makes sense to do so. We were *very* constrained on the total number of UCBs we could have, based on architectural point-to-point (no switch) FICON limits, and so we eliminated ALL of our mod-3 3390s a couple of years ago. We now have only mod-9, mod-27 and mod-216 devices. (FWIW, the most popular -- and most numerous -- ended up being the mod-27s.) It's like a breath of fresh air! -- Phoenix Software International Edward E. Jaffe 831 Parkview Drive North El Segundo, CA 90245 http://www.phoenixsoftware.com/ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
