Too many open files

Last week tomcat log file report many error about "Too many open files" when it has high traffic. Some in catalina_log say

2007-04-07 16:13:40 HttpProcessor[80][272] Starting background thread
2007-04-07 16:13:40 HttpConnector[80] accept:
java.net.SocketException: Too many open files

and here is from localhost_log
2007-04-07 16:13:40 StandardWrapperValve[myservlet]: Servlet.service() for servlet myservlet threw exception
java.io.FileNotFoundException: /home/log/mylog_070407.log (Too many open files)

This is because too many file descriptors're opened by tomcat. File descriptor can be limited in both system level and shell level.

To check maximum number of fd in system type 'cat /proc/sys/fs/file-max'. In my case it is 65536(someone said it should set to 200000). Tomcat error when try to open socket number 272 so I think 65536 is ok for me for now. Anyway if u want to set it add 'fs.file-max = 200000' to /etc/sysctl.conf
pnix@pnix-a7:~$ cat /proc/sys/fs/file-max

next go check shell level 'ulimit -n' give me 1024. This is reasonable b'coz I have three servlet each need about 3-4 fds per request. So I change this limit by add
* soft nofile 2048
* hard nofile 2048

in file /etc/security/limits.conf

To get the total number of handles that are used by process xxx
lsof -p xxx|wc -l


Geekygecko said...

Thanks for the tip. That has fixed my Glassfish issue.

I added large values just to be sure:
* soft nofile 65535
* hard nofile 65535

Great blog, I bookmarked it straight away.

Anonymous said...

Great Blog !!!, Thanks for all

Rowland Mynhardt said...

for the settings of
* soft nofile 2048
* hard nofile 2048
to take pleace must the pc be restarted?

pnix said...

rowland, sysctl.conf can reload at runtime with command
sysctl -p

Anonymous said...

thank you

Anonymous said...

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Brad Fallon said...

Why can't I get the website "world net daily" on the computer for two hours? Has it been sabotaged?

fico score said...

I am writing a program in Foxpro dos based. Error i am facing is Too Many files are open.config.sys changed.NA

Anonymous said...


Many many thanks. Thanks and only thanks. I was struggling last 2 days to solve this problem.

Thanks again.

Binod Suman

Rulett Fogalomtár said...

Can one erase saved files from rewritable CD using Nero start-smart essentials?

Quick Halloween Costume Ideas said...

while i am useing my computer too many files open it self and closeing as well why it is happing?

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Sandler said...


I do have the same kind of issue, But, looking for different type of solution.
I am looking for a script to start weblogic server, once * soft nofile 2048
* hard nofile 2048 is done. with passing the PID for each instance to lsof, weblogic put the pid # in the log directory.Please, help me with the Warper or any Script

Rogarema said...

What if I have the limit set to 32768 and I become the error message?

witeX said...

I't helps, when u simply login to system. If use `su` to user, need uncommtent one row in /etc/pam.d/su
"session required pam_limits.so"