Centos – Will open files limit in Centos affect HTTP connections? Does the limit apply to a single session or all sessions

centosulimit

When I do a ulimit -n I got 256, I assume it means I can open 256 files at the sametime.
Does it means I can open 256 files with one single session? or all sessions?

For example, I logined to my server with username "abc" (via putty/ssh), and open 200 files, with the session still running, I logined to the same server again with the same username "abc" (via putty/ssh), I can open only another 56 files? or I can open another 256 files?

Lastly, does this limit also restrict number of http connections? e.g. with the above example, I have opened 200 files, and then I use "wget" or "curl" to make http connections.

Thanks

Best Answer

ulimit is a bash builtin, so it applies only to the shell, and particularly any processes created by the current shell. Hence if you change it for any reason you will have to do so in a persistent way.

You might want to checkout the /etc/security/limits.conf file for setting session limits on a per-user basis. (which appears to be the CentOS preferred method)

you can see open files using the lsof -P | grep $somepid command

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