About semaphores

Bill Moran wmoran at potentialtech.com
Fri May 23 06:42:54 PDT 2003

Vladimir Sysoev wrote:
> I install Iserverd on my FreeBSD 4.6 server and it reports to 
> /var/log/messages : Not enough semaphores. change kernel parameters.
> I try to use sysctl kern.ipc... but these parameters are read only.
> 1. Does anybody know about how to increase maximum semaphores counts?
> 2. Where can I obtain information about kernel(sysctl) parameters (books 
> manuals and others).

The only way I know of is to compile a custom kernel.
See /usr/src/sys/i386/conf/LINT for information on semaphore settings.
Also, the PostgreSQL folks use semaphores a lot and have some
documentation on how to get enough semaphores (and other shared memory)
on FreeBSD for different needs.  If you install the PostgreSQL port,
it installs the file /usr/local/pgsql/post-install-notes which has
information on how to jack up shared memory usage (including semaphores).
This file is likely to be available on the web as well.

Bill Moran
Potential Technologies

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