운영중인 웹서버가 문제가 생겼습니다.

운영하고있는 웹서버가 있습니다. 운영웹서버가 문제 가있어 확인해보니
DB쪽에서 세션 많이 들어와서 과부하가 걸렸습니다. 그래서 임시 조치로 세션 제한 폭을 넓혀
db 다시 재가동후 (이때까지는 웹서버 쪽에 는 이상이 없었습니다.) 그런후 다음날 어제와 같은시간때에
웹서버쪽에 문제가 생겨 운영중인페이지가 열리지않았습니다 DB쪽 확인결과 DB쪽에 세션은 많이 붙어있었으나
접속이 나 쿼리쪽에는 이상이없었고 아파치로그를 보니 이런 로그가 발생되었습니다.

[Thu Jun 28 13:09:16 2007] [warn] child process 19921 still did not exit, sending a SIGTERM
[Thu Jun 28 13:09:16 2007] [warn] child process 19922 still did not exit, sending a SIGTERM
[Thu Jun 28 13:09:16 2007] [warn] child process 19923 still did not exit, sending a SIGTERM
[Thu Jun 28 13:09:16 2007] [warn] child process 19924 still did not exit, sending a SIGTERM
[Thu Jun 28 13:09:16 2007] [warn] child process 19925 still did not exit, sending a SIGTERM
[Thu Jun 28 13:13:44 2007] [error] child process 17217 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17067 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 18477 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17064 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17080 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17279 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 18653 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17271 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17273 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17276 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17266 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17081 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17274 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17277 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17281 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17608 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 18476 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17284 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 18453 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17286 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 17610 still did not exit, sending a SIGKILL
[Thu Jun 28 13:13:44 2007] [error] child process 19925 still did not exit, sending a SIGKILL`
[Thu Jun 28 13:14:15 2007] [error] could not make child process 17217 exit, attempting to continue anyway
[Thu Jun 28 13:14:15 2007] [error] could not make child process 17067 exit, attempting to continue anyway
[Thu Jun 28 13:14:15 2007] [error] could not make child process 18477 exit, attempting to continue anyway
[Thu Jun 28 13:14:15 2007] [error] could not make child process 17064 exit, attempting to continue anyway
[Thu Jun 28 13:14:15 2007] [error] could not make child process 17080 exit, attempting to continue anyway
[Thu Jun 28 13:14:15 2007] [error] could not make child process 17279 exit, attempting to continue anyway
[Thu Jun 28 13:14:15 2007] [error] could not make child process 18653 exit, attempting to continue anyway

동시접속 부하로 인한 에러같은데 사내인트라넷이라 아무리많아도 동시접속자가 20명을 넘기 힘든데
갑자기 이런현상이 일어나서 일단 웹서버를 다시 리붓했지만 조만간 또이런현상이일어날꺼같아
문제가 됩니다.
rw-r--r-- 1 root root 190344124 6월 28 18:15 access_log

혹시 아파치 의 로그 용량 때메 그럴수가있는건지?

아니면 어떤문제가 있는지 비슷한현상을 겪으신분있으면 도움좀 요청합니다.
참고로

웹서버에서 #ps -ef 하면 현재운영중인 페이지의 dns 로 nobody 의 프로세스들이 많이 올라왔었습니다.

운영하는페이지 상에는 로직문제는 아닌거같습니다.