Re: Glibc, large PIDs etc (Was: Killing clones) (fwd)

Tim Wright (timw@kryten.aracnet.com)
Tue, 26 Aug 1997 08:08:59 -0700

jlnance@avanticorp.com said:
> Since glibc can deal with a 32 bit PID and no one is bumping into a
> 32K process limit yet perhaps we should just wait for a while before
> changing the kernel. If we do that than perhaps by the time we really
> need to switch to 32 bit PIDs (hopefully 5 to 10 years) everything
> will be glibc based and just work.

Ummm...
no.
Whilst I don't think Linux users are likely to be hitting the limit too soon
since I believe the majority of Linux users are using "small" systems, the
limited size of the process id "name"space is getting close to being an
issue for large scale Unix systems.

If I have a system supporting 12,000 database users and the database
architecture uses two processes per user, I've used 24,000 of my 30,000
available pids (MAXPID is normally 30,000 for SVR4ish systems) or 80%.
That caps me at < 15,000 connected users. This is a real limit.

The above is not an entirely hypothetical example...

t

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