How to increase FD_LIMIT in 32-bit and 64-bit m/c?
 

Hi all,

Can anyone explain how to increase the file descriptor limit in Ubuntu 10.04 (OS), for both 32-bit and 64-bit m/c?

How to find the upper limit of FD's that can be increased in the system and how to verify that the increased FD's are not contributing in any side-effect in the performance of the system.

Detail explanations will be good.


Thanx,
v16

Try /etc/security/limits.conf

To view the current values, issue "ulimit -a".

Not sure if the limits controlled here represent what you wish to change. Sounds like you wish to change the limit of descriptors allowed by the kernel which is in code and controlled when you compile the kernel; however you can have a limitation or allowance on the amount of open file descriptors per user using the ulimits.

Thanx rtmistler

But how much fd-limit can be increased in 32-bit or 64-bit system and will that has any side effect on the performance of the system. Basically i referring to the server performance like apache etc.

Thanx

More open descriptors for anything means more open sessions, more resources in use, more memory, more shared usage of the CPU. Therefore the more RAM you have and the faster CPU you have, the better.

I'm not sure, my experience with the limitations on open file descriptors may be out of date, I thought the maximum used to be 65535 per process.

My understanding is that the apache webserver works better with more file descriptors and their server apparently tries to increase the amount of allowed descriptors when it interacts with the operating system. I think you'd see errors that you've run out of descriptors which indicates that your system limits should be altered, if possible, to help the server's performance.

Sorry, that's not probably exactly what you were looking for. There are likely wiki's on the Apache webserver and how to tune it for better performance.