12-17-2002
You're worried about file descriptors?
File descriptors use a trivial amount of memory and I don't understand what it is that you're worried about. Each time you remove a file descriptor from your system you get back the space required to store two shorts and one pointer. Are you really that tight on swap space?
Your average fd will also require a file table entry, but even that isn't a real big deal. If I open() a file, and then dup()it 100 times, I will have 101 fd's all pointing at the same file table entry. That would be a little crazy, but lots of processes have stdout and stderr pointing to the same file table entry, so assuming a correspondence between fd's and open files is wrong.
Any process can change its soft limit to any value that does not exceed its hard limit. Any process may lower its hard limit. A root process can raise its hard limit.
We have some 5.5.1 systems and we use lsof on them all the time. But pfiles in included with 5.5.1 and might be a better choice for you anyway.
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