troubleshooting Question

Linux File Descriptors ..

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Unix OSLinuxLinux Distributions
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Dear All
I have a couple of questions regarding file descriptors (handles) and the command ulimit.
Now the thing is I know about Ulimit..to get a snapshot about the file descriptors on the system I executed the following command :


[root@localhost mail]# cat /proc/sys/fs/file-nr
2520 0 206068
| | |
| | |
| | maximum open file descriptors permitted
| total free allocated file descriptors
total allocated file descriptors since boot

I took the appended descriptions from http://support.zeus.com/zws/faqs/200...iledescriptors
What I do not understand is that how these number are calculated if the total number of allocators since boot is 2520 and the available is 0 how can the
maximum open file descriptors permitted be bigger than that number?
I mean if the first number is used to describe the file allocators of one process in particular which is it ?

Another thing that confused me from the same article is the following phrase :

"In current (2.4+) Linux kernels, file descriptors are dynamically
created as necessary, but cannot be removed or reduced other than by
rebooting the server."

What does that mean, that in 2.4 kernels and above (I am using 2.6) file descriptors hang on to the process untill the system is rebooted..I think there is either something wrong with the way I understood this or ....

Can anyone shed some light on the issues mentioned above please ?
ASKER CERTIFIED SOLUTION
fgande

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