My mysqld goes to use 99.9% of CPU for variable time (between 2 - 20 minutes), and then goes back to normal 0.1% - 5%. Checked processlist: all is normal, 1 to 20 inserts or updates that last 2 to 5 sec, and about 20 process that are in Sleep Mode (maybe because the scripts don't close the mysql connection, but are they are closed in about 5 - 10 secs, I didn't make the scripts :P but the server was running fine the last 2 years, since is was made):

| 15375 | root                 | localhost             | stoc  | Query   |    0 | NULL             | show processlist                                                                                     | 
| 79480 | pppoe                | localhost | pppoe | Sleep   |    4 | NULL             | NULL                                                                                                 | 
| 79481 | pppoe                | localhost | pppoe | Sleep   |    4 | NULL             | NULL                                                                                                 | 
| 79482 | pppoe                | localhost | pppoe | Sleep   |    4 | NULL             | NULL                                                                                                 | 
| 79483 | pppoe                | localhost | pppoe | Query   |    0 | init             | UPDATE acc SET InputOctets="0", OutputOctets="0", InputPackets="unknown", OutputPackets="User | 
| 79484 | pppoe                | localhost | pppoe | Sleep   |    5 | NULL             | NULL                                                                                                 | 
| 79485 | pppoe                | localhost | pppoe | Sleep   |    5 | NULL             | NULL                                                                                                 | 
| 79486 | pppoe                | localhost | pppoe | Sleep   |    5 | NULL             | NULL                                                    

Checked raid, seemns OK:

[root@db2]# cat /proc/mdstat 
Personalities : [raid5] [raid4] [raid1] 
md0 : active raid1 sdd1[3] sdc1[2] sdb1[0] sda1[1]
      136448 blocks [4/4] [UUUU]

md1 : active raid5 sdd2[3] sdc2[2] sdb2[0] sda2[1]
      12023808 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]

md3 : active raid5 sda4[1] sdd4[3] sdc4[2] sdb4[0]
      203647488 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]

md2 : active raid5 sda3[1] sdd3[3] sdc3[2] sdb3[0]
      24024576 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]

unused devices: <none>
[root@db2]# 

top sees my mysqld cpu load, but nothing else seems to be wrong:

[root@db2]# top

top - 17:56:05 up 7 days,  3:55,  3 users,  load average: 32.93, 24.72, 22.70
Tasks:  75 total,   4 running,  71 sleeping,   0 stopped,   0 zombie
Cpu(s): 63.4% us, 36.6% sy,  0.0% ni,  0.0% id,  0.0% wa,  0.0% hi,  0.0% si,  0.0% st
Mem:   1988824k total,  1304776k used,   684048k free,    99588k buffers
Swap: 12023800k total,        0k used, 12023800k free,   951028k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                         
 5754 mysql     19   0  236m  57m 5108 R 99.9  2.9  21:58.76 mysqld                                                                                          
    1 root      16   0  7216  700  580 S  0.0  0.0   0:00.39 init                                                                                            
    2 root      RT   0     0    0    0 S  0.0  0.0   0:00.00 migration/0     

Repaired all mysql databases, reindexed raid ... I'm running out of ideeas ...

Anyone has an ideea what can go wrong with this server ?

Thank you