RE: performance with very active threads

Tam As you already know, you have a major problem with your disk subsystem which you are correcting with RAID10. > 1004 1381386242 16652000 122880000 2472 V 2496 12504 SHMVIRTSIZE: You have 120Mb allocated here, but at this time you only have 20Mb (2496) used. How large does this become? It appears you have too much allocated. You can reduce this and allocate more BUFFERS. You have 756Mb Ram, and using 323Mb for Informix. Increase BUFFERS. I suggest somewhere between 200000 and 250000. Check kernel shared memory parameters first. This will also reduce disk IO! Also look at read cache and bufwait. Use the RA parameters 32/24 suggested elsewhere. MW -----Original Message----- From: owner-informix-list@iiug.iiug.org [mailto:owner-informix-list@iiug.iiug.org]On Behalf Of Tam McLaughlin Sent: Friday, September 08, 2000 1:48 AM To: informix-list@iiug.org Subject: Re: performance with very active threads Murray Wood wrote in message <8p6he5$ct5$1@news.xmission.com>... > >Tam > >Comments below on onconfig. > >Is KAIO available on SCO Unixware? Your AIO maxlen look long to me. KAIO is not supported on unixware 7.0.1. We will be upgrading the OS in a few months and will also upgrade to IDS2000 > >The problem looks to me in the application. The engine must wait for all >threads to get out of critical sections before starting the checkpoint, but >then there is the time taken to clean all buffers etc on the checkpoint. >The former is often the longer in duration. > >Is you disk I/O maxing out, particularly at checkpoints, and on which >drives? >Is is I/O even between your disk drives? If not, move tables to even the >load. > Not sure what you mean but using sar, the %wio is > 50. Moving from RAID5-RAI10 will, I believe, help. It was mentioned to increase the physfile size, but at checkpoints, it is always < 5%. >PHYSDBS rootdbs Move elsewhere? Logical logs also! I intend to do both these >PHYSFILE 10000 Increase, for increased checkpoint interval > BUFFERS 96000 Far too few. How much memory do you have? 756 Mb RAM >>SHMVIRTSIZE 120000 Check is this used? If not move memory to buffers. i have this: Informix Dynamic Server Version 7.30.UC10X2 -- On-Line -- Up 9 days 06:13:34 -- 323080 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 1003 1381386241 a000000 207953920 4032 R 25378 7 1004 1381386242 16652000 122880000 2472 V 2496 12504 1005 1381386243 1db82000 753664 608 M 87 5 1006 1381386244 1dc3a000 753664 608 M 84 8 1007 1381386245 1dcf2000 753664 608 M 84 8 Total: - - 333094912 - - 28129 12532 >CKPTINTVL 300 Suggest you increase - 30 mins suggested >LRUS 63> >>RA_PAGES Set both of these >RA_THRESHOLD You may set to 0 with too few buffers >DBSPACETEMP tempspace Try 3 on different disks >>>