How to reduce IOWAIT in linux


 
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# 1  
Old 07-13-2007
How to reduce IOWAIT in linux

Hi All,

Any ideas how to reduce IOWAIT and increase disk speed on Linux server.

Server has 4 CPUs and with 8GB RAM.

Thanks in advance,

Regards,
Bache
# 2  
Old 07-13-2007
Not knowing much about your machine here are a few thoughts.

1. Are you using the fastest disks you can, both rotational speed and transfer speed and can your disk controllers support the transfer rates?

2. Consider having a number of disks so binaries live on different disks to data. This will reduce the time spent waiting for seeks to occur.

3. In certain configurations, a RAID arrangement may speed up access to disks.

4, Are you using delayed writes?
# 3  
Old 07-15-2007
Here is an interesting article regarding performance tweaks for Linux...

http://www.linux.com/feature/116693

Quote:
The hdparm command ("hdparm" stands for "hard disk parameters") allows you to examine and modify drive configuration. Not all modifications are good: some will lower the performance, and some can even be wildly destructive, leading to data loss. The man hdparm command shows you all the options, and highlights the dangerous ones.
# 4  
Old 07-16-2007
Another tool that will suggest good options is "iozone - filesystem benchmark tool".
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