Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : extreme CPU usage on my server

[mr-cracker]

Hello there,
I'm getting very high cpu usage but i don't know what is causing that here is top otuput


top - 06:26:00 up 7:42, 1 user, load average: 0.00, 0.00, 0.00
Mem: 4045976k total, 2086628k used, 1959348k free, 62480k buffers
Swap: 8385920k total, 0k used, 8385920k free, 425912k cached
Cpu(s): 0.1%us, 0.2%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.1%si, 0.0%st

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
8756 root 15 0 13188 1600 860 R 1.0 0.0 0:19.91 top
1 root 15 0 10364 672 572 S 0.0 0.0 0:01.25 init
2 root RT -5 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root RT -5 0 0 0 S 0.0 0.0 0:00.03 migration/1
6 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1

do u see CPU, that 99.7%id, which i don't know what is it

any helps please

[mr-cracker]

digging more i found 97%id means 97% of CPU is idle, but yet i couldn't connect to my server. could it be related to buffers or cached mem??

[foobic]

How are you trying to connect? (web / ftp / email / something else?). Judging by the top listing it's probably nothing to do with memory - more likely a service down or firewall issue.

<<Moved to Hosting Security and Technology>>

[mr-cracker]

connecting through web,
and i agree with you, i opened a ticket about that but meanwhile if there is anything i can do i want to do because my website is not functioning properly

[foobic]

Do you have root access? If so you could try:

service httpd status

or if you need to restart it:

service httpd restart

[diman]

I'd suggest to check firewall rules as well. According to top, there's no issue with CPU.

[znetindia]

Hi,

check constantly your top -s -c on server and find your top high usage services.
Check their concurrent connections in netstat
Check iftop with runtime connections of your ethernet.
check SYN_REC with netstat and find out how many active SYN_REC are occurring on the server. The number should be pretty low, preferably less than 5. On DoS attack incidents or mail bombs, the number can jump to pretty high.
Find out those IP's which you find making high concurrent connections, try to stop them in your /etc/hosts.deny file.

[gzoli]

99.7% idle CPU, your server not used.

[SiniStraL]

You can use server httpd fullstatus

[znetindia]

Hi,

Run this command :
# netstat -n -p|grep SYN_REC | wc -l
Find out how many active SYNC_REC are occurring on the server. The number should be pretty low, preferably less than 5. On DoS attack incidents or mail bombs, the number can jump to pretty high.