UNIX for Dummies Questions & Answers

// AIX 6.1 & Power 7 server

I have maxuproc set to 16384.

Code:

 lsattr -El sys0 -a maxuproc
maxuproc 16384 Maximum number of PROCESSES allowed per user True

What is the maximum number of maxuproc we can go for?

If I increase maxuproc to the higher number, what would be ramifications?

I am also wondering why 16384 (16*1024) is recommended?? I am not sure 16384 is the recommended maxuproc for most cases/systems??

Please advise.

I'm not an AIX expert - things there are often not as they are else where.

The idea of limiting concurrent processes for a user stems from problems like fork bombs.
These simply create new child processes that create new child processes.

This is an extreme case. And not the norm by any means.

But the idea is to prevent poorly coded processes from taking over all available new process slots and preventing legitimate processes from running. The system grinds to a halt.

So for other systems you can achieve the same with ulimit settings. maxuproc allows a hard setting for ulimit - in a sense. You should never give over, by default, a large percentage of the available user process slots on a system to one application. Oracle not withstanding. Oracle "assumes" ownership of whatever machine/virtual it is on. It used to play nice with others, not anymore.