Hi Mauri, We have done this in all but our largest data sharing Sysplex which is scheduled next month.
Currently there is an open interesting APAR OA39941. If you exceed 80% of Large Pages you will get an exciting red hi-lite message from SRM. Nothing bad may happen but some ISV products may react to the bits that are set in control blocks. It would be best to avoid exceeding SRM thresholds of Large Pages till you apply the PTF for OA39941 or test this condition in an identical non-production LPAR at your site with your software mix. DB2 will get its storage even over 100% allocated large pages and will work fine functionally but you would get error message IRA120E LARGE FRAME SHORTAGE. We are managing the LFA size which can be set only at IPL carefully with our DBA's to avoid exceeding the 80% threshold. We already had procedures in place to manage storage with them because we use almost all page fixed buffer pools and they need to work with closely on budgeting real storage use and management of the available frame queue in each LPAR. APAR Identifier ...... OA39941 Last Changed ........ 12/09/25 MESSAGES IRA120E AND IRA121E SHOULD BE INFORMATIONAL SRM monitors large frame usage and issues message IRA120E when 80% of all large frames in the system are in use and then issues message IRA121E when 95% of all large frames in the system are in use. These messages were implemented as highlighted action messages but they are really only informational messages. Best Regards, Sam Knutson, GEICO System z Team Leader mailto:sknut...@geico.com (office) 301.986.3574 (cell) 301.996.1318 "Think big, act bold, start simple, grow fast..." -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Mauri Kanter Sent: Thursday, October 18, 2012 8:54 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Question on DB2 and LFAREA (large-pages) Good day !!! I'm looking on how to implement DB2 and its large page support. One question ... Suppose I allocate an LFAREA of 4.5 GB based on the fact that the fixed DB2 bufferpools use 4GB. Then my DBA requests to dynamically ALTER the bufferpool to 5GB. What's happen then? a - Is it allocated part with large pages and part with 4K pages? b - All with 4K pages? c - Not possible, need to IPL? d - Other Thanks in advance for your hints. Mauri. ==================== This email/fax message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution of this email/fax is prohibited. If you are not the intended recipient, please destroy all paper and electronic copies of the original message. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
