On Fri, 4 Nov 2005 23:01:39 +1000, ibm-main <[EMAIL PROTECTED]> wrote: >> There is absolutely nothing wrong, incorrect, improper, or unexpected >about >> any system space (GRS) using as much memory above 2G as it wants, provided >> that it has documented that use so that customers can properly plan. Note >> that I am differentiating GRS from DB2 in this regard. > >Hey Scott, are you ears burning mate ???? .... ;-)
Not particularly... GRS' use of above the bar storage is closely managed and is, intentionally, not left to the user to manage. GRS gets its memory objects at system initialization time and NEVER gets any more. If these memory objects cannot be obtained, the system will not come up. The above the bar storage is mostly guard area to surround 2GB ranges that map to areas used for extensions to GRS control blocks, required to enable the system support to the greater number of concurrent ENQs that MIP LPARs request at z/OS 1.6 and up. See http://shareew.prod.web.sba.com/client_files/callpapers/attach/SHARE_in_Bos ton/s2884SFa.pdf (watch the wrap) see charts 57-63. Any frame in these above the bar areas that is not populated is released from GRS' working set, minimizing the impact to the system. If you have few outstanding ENQs, the amount of data 'up there' is minimal. An alternative to this approach would have been to use dataspaces in the same way. Would there have been the same hue and cry if we had added 4 additional dataspaces, rather than 8GB (usable) of 64-bit memory objects? Scott Fagen z/OS Core Technology Design IBM Poughkeepsie ---------------------------------------------------------------------- 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
