Optimization of BD

Hello everyone,
I have a base to give Postgress hosted on a server Dedicate
This database am receiving an many connections each day
There are times to spit comics
I commcé make a little research and using the iostat command, I got some results
I'd make sure of the meaning of words% idle, and see if you have an analysis of these results
thank you


root@new-appl:~# iostat
Linux 3.2.0-29-generic (new-appl) 04/10/2013 _x86_64_ (4 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
7.60 0.00 1.71 0.02 0.00 90.67

Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
sda 3.40 48.56 44.11 185423120 168416640

root@new-appl:~# iostat
Linux 3.2.0-29-generic (new-appl) 04/11/2013 _x86_64_ (4 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
7.62 0.00 1.70 0.02 0.00 90.66

Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
sda 3.47 52.96 43.97 205562105 170677108

root@new-appl:~# iostat -x
Linux 3.2.0-29-generic (new-appl) 04/11/2013 _x86_64_ (4 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
7.62 0.00 1.70 0.02 0.00 90.66

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
sda 8.70 3.11 0.96 2.52 52.95 43.97 55.83 0.01 4.22 1.40 5.29 0.26 0.09

root@new-appl:~# iostat -x
Linux 3.2.0-29-generic (new-appl) 04/11/2013 _x86_64_ (4 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
7.62 0.00 1.70 0.02 0.00 90.65