RE: Memory Usage

Personally, allocating 254 MB for BUFFERS with only 512 MB RAM is not advisable. For the following reasons: - BUFFERS reside in the resident portion of memory if you do the math allocating an additional 100 MB to BUFFERS will use approx. 300 MB for the resident portion. - You are already using approx. 100 MB for the virtual portion. You might use more if Informix decides to allocated another virtual segment. - Oninit processes also uses the servers RAM - HP-UX will also use RAM Based on the above reasons, you'll easily use up all of your physical memory. If it does you'll then be using a lot more of your swap space, which means more I/O. And if your applications run on the same machine as Informix, you'll definitely see a lot of swapping going on. Of course you can always try out your plan and monitor swap space use. Don -----Original Message----- From: Tony Flaherty [mailto:aef@mfs.misys.co.uk] Sent: Tuesday, September 26, 2000 7:31 AM To: informix-list@iiug.org Subject: Memory Usage HpUx 10.20 Dual Processor K200 512Mb RAM Informix Dynamic Server 7.30.UC7 I want to allocate more memory to my Informix server, but I need some advice on how to examine the current memory usage of the machine. The machine runs an OLTP Informix database with approx 100 users, both the client and the server applications run on the same machine. I currently have 156Mb allocated as BUFFERS to IDS and I'd like to increase this to 254Mb. I'm inclined to just do this as we ugraded the machine from 256Mb to 512Mb about a year ago, so even if I do allocate half of this to IDS I've still got more left for the OS and Client apps than I had before, but I'd like a more proffesional way of making this decision ;o) Some possible usefull info;- swapinfo Kb Kb Kb PCT START/ Kb TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME dev 524288 60252 464036 11% 0 - 1 /dev/vg00/lvol2 dev 524288 61880 462408 12% 0 - 1 /dev/vg04/lv_swap2 reserve - 598300 -598300 memory 397140 334560 62580 84% sar -w HP-UX hpk200 B.10.20 U 9000/819 09/26/00 00:00:00 swpin/s bswin/s swpot/s bswot/s pswch/s 01:00:00 0.99 0.0 0.99 0.0 1040 02:00:00 1.00 0.0 1.00 0.0 687 03:00:00 1.00 0.0 1.00 0.0 452 04:00:00 1.00 0.0 1.00 0.0 77 05:00:00 1.00 0.0 1.00 0.0 73 06:00:00 1.00 0.0 1.00 0.0 415 07:00:00 1.00 0.0 1.00 0.0 79 08:00:00 1.00 0.0 1.00 0.0 77 08:20:00 1.00 0.0 1.00 0.0 88 08:40:00 1.00 0.0 1.00 0.0 240 09:00:00 1.00 0.0 1.00 0.0 261 09:20:00 0.99 0.0 1.02 0.1 717 09:40:00 0.95 0.0 1.02 0.3 1286 10:00:01 0.98 0.0 1.02 0.2 485 10:20:01 0.99 0.0 1.01 0.3 555 10:40:01 1.00 0.0 1.01 0.1 598 11:00:00 0.99 0.0 1.00 0.1 469 11:20:00 0.99 0.1 1.01 0.4 485 11:40:00 0.98 0.0 1.00 0.2 574 12:00:00 0.99 0.0 1.00 0.2 479 12:20:00 1.00 0.1 0.98 0.1 450 Average 1.00 0.0 1.00 0.1 416 onstat -g seg Informix Dynamic Server Version 7.30.UC7 -- On-Line -- Up 16:55:51 -- 298184 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 777 1381451778 c0bda000 2711552 652 M 325 6 776 1381451777 d1235000 202932224 5572 R* 24765 7 (shared) 1381451777 dd3bd000 102408192 2172 V 7365 5136 Total: - - 308051968 - - 32455 5149 (* segment locked in memory) If there's any other info you'd like to see please let me know. TIA -- Tony Flaherty Snr. A/P, Informix DBA, HpUx Admin, Gimmi a broom! MFS Ltd.