Memory solves all problems. Tom Moulder quoting Ted VanDuyn
-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Knutson, Sam Sent: Friday, November 09, 2007 12:36 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: Real storage usage - a quick question Hi, You are going to do a great service to the business if you can make the case to use a valued asset you already own to improve service. Go for it! You can absolutely leverage the better part of 2 gigabytes of memory just for DB2 buffer pools in V7. Pay attention to peak storage demands in DB2xDBM1 address space and remember that in V7 you can do some tricks like data spaces you lose in V8. Get more detailed advice on the DB2-L list. I think the level of concern may be to high here. 10G really is not that much even on z/OS 1.7 we had LPARs several times that size without any problem. There are some IEAOPTxx parms that can minimize RSM overhead on 1.7 that have been documented by IBM now but we found that made a difference on really large LPAR's 40G - 80G not 10G LPARs. Remember "There is NO I/O like NO I/O"! You can exploit extra real memory with products you already have in hand easily. SyncSort or DFSORT will both exploit more memory to improve performance easily. Some adjustments may help things run the way you want. Both SyncSort and IBM provide good advice as well as good software. Exploit VLF! Increase your cache size for CSVLLA and look at other exploitation of LLA/VLF. The best paging is no paging. Paging on z/OS is a waste of cycles put enough storage on you don't normally page. DB2! One of DB2's best defenses against I/O is sufficiently large buffer pools intelligently allocated with DB2 objects and thresholds. DB2 V7 is OK. DB2 V8 is much better at exploiting LOTS of storage. Spare storage? Are you planning on adding an LPAR? If not setup your HSA with plenty of room for dynamic growth and use the rest. At $8K/G or $10/G it seems wasteful to leave it idle. Best Regards, Sam Knutson, GEICO System z Performance and Availability Management mailto:[EMAIL PROTECTED] (office) 301.986.3574 ((((DO SOMETHING!) SMALL) USEFUL) NOW!) - computer pioneer Bob Bemer -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Max Scarpa Sent: Wednesday, November 07, 2007 5:00 AM To: IBM-MAIN@BAMA.UA.EDU Subject: Real storage usage - a quick question Esteemed listers I've a problem but I haven't any answer to it or better I've different answers. Say we have a machine with, just to say, 10 Gb of real storage. Only 5 are used by the only LPAR defined (actually there's another very small LPAR, but it's real small), which is a WLC LPAR and often it's CPU capped. 5 Gb remain unused. I asked why, as I'd like to enlarge my bufferpools in DB2 (for instance). I've got these answers: - Increasing real storage increases cpu overhead to managed more memory blocks in a cpu-constrained machine. - Increasing real storage causes more workload so more chanches to hit WLC capping. - It's better to have some spare storage (5 Gb ?). Our workload is increasing and we have some occasional paging spikes. DB2 doesn't perform well due to too small pools. According listers' experience, is using the most part/all real storage (perhaps with a spare memory for future incrases) a real problem ? Did anyone experimented any problem ? What are guidelines ? Thank you in advance Max Scarpa ==================== 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 [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.15.26/1120 - Release Date: 11/9/2007 9:26 AM No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.15.26/1120 - Release Date: 11/9/2007 9:26 AM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.15.26/1120 - Release Date: 11/9/2007 9:26 AM ---------------------------------------------------------------------- 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
