Re: Online 7.10 performance on Stratus and others

zondag@xs4all.nl (Jan-Evert Zondag) wrote: Some additional things you might look at: Does your version of UNIX support kernel asynchronous IO? If so, then informix allocates one virtual processor per CPU to handle IO. Here again, the more cpus you have the better your performance will be. Also, are you using any kind of RAID setup for your rawdisk? This can have a tremenedous negative impact on throughput, especially for writes. We use a RAID 5 setup. Writes are relatively slow but our reads (98% of what we do, scream). Monitor your SAR output during your testing and examine you onstat -p output to try and identify your bottle necks. Use onstat -D to monitor actual chunk IO. Are you using data partitioning? If you are not using a RAID configuration, then you might want to consider it. If you are using RAID, then avoid partitioning. >In article <3qg2a5$1d1e@firehose.mindspring.com>, > ekelley@mindspring.com (Ed Kelley) wrote: >>One thing you might look at is the PDQPRIORITY and MAXPDQPRIORITY >>paramteres in your config file. If both are set to 100, then a query >>will use 100% of the system's resources to complete that query. A >>better alternative is to set PDQPRIORITY to "off". Then control the >>actual usage on a job by job bases using the environmental variable >>PDQPRIORITY. >> >>Before I did this, I had the same problem with 7.1 on an AT&T 3555 >>server. Now, it smokes! >> >>Something else to think about is 7.1 is heavily multithreaded. A dual >>processor system does not really take advantage of this. More cpus >>greatly improve performance. >> >thanks for your fast response. We will run a few extra tests. We had >PDQPRIORITY = OFF but we did not know it could be controlled by setting an >environment variable. >But... our performance degradation also occurs when a number of update >processes is running. >--------------------------------------- >Met vriendelijke groet (dutch for: with kind regards) >Jan-Evert Zondag >email: zondag@xs4all.nl Ed Kelley, Senior Specialist AT&T Network Systems - CIO Email: ekelley@mindspring.com or ekelley@attmail.att.com or ekelley@msn.com or ekelley@ichange.com WEB page: http://www.mindspring.com/~ekelley/html/ekelley.htm