I would reach out to Marna Walle at IBM. She has been collecting PARMLIB information from quite a few sites.
On Wed, 6 May 2026 at 20:05, Glen Garrison <[email protected]> wrote: > I have not specifically looked at what the general population have > specified for RSU. > But I do know that many systems out there have initial and reserved > specified and have seen where some set rsu equal to their reserved, so some > must be config'ing that offline for use by other lpars. Generally > RSU=OFFLINE. I have also seen RSU=0 with reserved defined. > Do the hardware guys have this information from active systems/lpar > configurations out there? At least, how many have defined reserved central > storage. One would think if they have reserved defined they would have a > corresponding RSU to cover it. > > > ________________________________ > From: IBM Mainframe Discussion List <[email protected]> on behalf > of Jim Mulder <[email protected]> > Sent: Wednesday, May 6, 2026 2:21 PM > To: [email protected] <[email protected]> > Subject: [EXTERNAL] Does anyone specify an RSU other than 0 in IEASYSxx? > > Does anyone still specify an RSU other than 0 in IEASYSxx, and use the > CF STOR command to take storage offline from a z/OS system? > > The ability to deconfigure storage from a running MVS system was > requirement on the old bipolar MP systems in order > to dynamically reconfigure from single image to physically partitioned > mode. The bipolar machines have been obsolete for decades, and the CMOS > machines never had any concept of physical partitioning. > > CF STOR can be used on current machines to take storage offline from a > running z/OS partition so that it can be reassigned to a different > partition, presumably > as a manual process for workload balancing reasons, But does anyone > really do that? Specifying an RSU other than 0 to describe the amount of > storage that can > be dynamically taken offline requires that amount of storage to be set > aside and not used for common storage fixed pages or long term fixed pages > owned by nonswappable > address spaces. Managing that separation is a complex process which can > reduce system performance and reliability. > > Jim Mulder z/OS Diagnosis, Design, Development, Test IBM Corp. > Poughkeepsie NY > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
