Slow-queries - Problems with mysql configuration

Hello
I have portal on server:
Intel Bi Xeon Quad
8x 2.66+ GHz
12 MB L2 - FSB 1333 MHz
64 bits
RAM: 12 GB FBDIMM DDR2
Hard drives: 2x 147 GB SAS 15 000 tr/min - RAID 1 HARD

But sometimes i have problem with mysql. When it is working sometimes there are errors in slow-queris. I see there are lags for about 30 seconds and i can’t find what is wrong. Look at STATUS in phpmyadmin.

http://hosting04.imagecross.com/image-hosting-11/2502info.pn g
I think this problem can be connected with these errors and my question is how can i fix them and where can be problem with slow-queries.

Here is my.cnf
http://phpfi.com/383720

Thanks for reply

P.S
sry for my english. I am begginer :wink:

check ur slow-query’s execute plan.

Last time I heard about 30 seconds lags it was because problems with RAID. Check cpu and hdd performance, if there are 100% then You should check Your hardware.

There could be also problems with Your tables, queries and indexes. Did You check select queries with explain ?

Status: DEGRADED
phy0 : SEAGATE ST3146854SS
Size: 136 GB
Status: FAILED
phy1 : SEAGATE ST3146854SS
Size: 136 GB
Status: ONLINE

Problem has been solved.

Thanks for all. )

Use Nagios or other monitoring tool to know about RAID failures as soon as they happen )