IBM Mainframe Discussion List <[email protected]> wrote on 07/07/2005 04:48:14 AM:
> To sum up: > I can safely move all my current 3390-03 pageds to 3390-09's on ESS with > dynamic (WLM managed) PAV's, two 3 GB pageds belonging to the same system on > each volume, ensure sure they are not used over 30%. Right? > > One question about the 30%: in the 3380 era, when a pageds was 625MB, > keeping utilization under 30% ensured 425MB free space, apparently enough > for the contiguous slot algorithm. In a 4 GB pageds, 30% utilization leaves > 2.8GB free for contiguous slots. Does this imply that the size of contiguous > slots has increased? The 25-30% recommendation is not coded into into the slot selection algorithms - it is simply to improve the probability of finding contiguous available slots. The slot selection processing was overhauled back in MVS/XA SP2.1.2 (around 1983), updated for block paging support in SP2.1.3, and hasn't changed much since then. The implemention is in module ILRIODRV, which is non-OCO, for those who wish to read the code on VPL or old microfiche. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
