Hi friends,
I want to share some of my observations which I found when debugging an issue with Apache reaching its MaxClient limit.
I am using apache-1.3.34 with PHP and ssl.
I was facing a frequent problem of Apache reaching its MaxClient Limit all of a sudden and use to stay in that state for a long time with no other request getting served.
This condition use to happen all of a sudden with no clues in the log files. I noticed one important thing in netstat, there were lot of UNIX stream sockets some in ESTABLISHED and CONNECTED state this use to haunt me a lot. Initially I ignored it since me too had used UNIX stream socket to communicate with the backend in my PHP scripts.
After keen observation to the netstat output I noticed that the UNIX stream sockets are getting created event though the PHP script was not called.
Finally I recompiled my apache with mod_status and got a report. I seen Lot of threads are stuck in DNS lookups and were not able to recover. I turned off the HostNameLookup from my conf file and belive me every thing went fine smoothly
The UNIX stream sockets were also the result of same. Things are working fine since yesterday. Apache is now able to serve 1000 users.
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Chidanand Gangur
Pune.
