iowait optimize

[hung]

Is there any way to optimize iowait? In my top

08:25:27 up 5 days, 18:01, 1 user, load average: 11.38, 5.77, 4.13
219 processes: 206 sleeping, 10 running, 1 zombie, 2 stopped
CPU states: cpu user nice system irq softirq iowait idle
total 15.0% 0.0% 1.5% 0.1% 0.7% 82.4% 0.0%
cpu00 10.4% 0.0% 1.8% 0.7% 2.6% 84.3% 0.0%
cpu01 14.9% 0.0% 1.8% 0.0% 0.1% 83.0% 0.0%
cpu02 22.0% 0.0% 1.1% 0.0% 0.0% 76.8% 0.0%
cpu03 12.6% 0.0% 1.4% 0.0% 0.1% 85.6% 0.0%
Mem: 1024328k av, 1006968k used, 17360k free, 0k shrd, 19704k buff
774628k actv, 144908k in_d, 17200k in_c
Swap: 1052248k av, 290520k used, 761728k free 621964k cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND
4307 nobody 15 0 14980 12M 3504 S 2.4 1.2 0:00 0 httpd
4260 nobody 15 0 14264 11M 2916 S 1.8 1.1 0:00 2 httpd
4298 nobody 15 0 10964 8196 3036 S 1.0 0.8 0:00 3 httpd
4300 nobody 15 0 13232 10M 3228 S 1.0 1.0 0:00 0 httpd
4267 nobody 15 0 11516 8068 2992 S 0.5 0.7 0:00 2 httpd
4270 nobody 15 0 13300 10M 2748 S 0.5 1.0 0:00 2 httpd
4282 nobody 15 0 14560 11M 2996 R 0.5 1.1 0:00 0 httpd
4222 nobody 15 0 14204 11M 2880 R 0.4 1.1 0:03 0 httpd
4230 nobody 15 0 12788 9716 2948 S 0.4 0.9 0:02 2 httpd

the iowait is so high, so it makes serverload high as well. Is there any idea?

thanks

[choon]

Which distribution is this and are you running on any RAID?

[hung]

No, I am running on a SATA HDD, and have the secondary SATA HDD for backup (not RAID). And the OS is CentOS 3.4

[choon]

Which linux distribution you are using?

[hung]

I am using CentOS 3.4