Re: running out of file descriptors

[Eric Bambach <bot403@cisu.net>]

On Monday 16 February 2009 01:09:42 Bryan Christ wrote:
> On Mon, Feb 16, 2009 at 12:18 AM, Joe Damato <ice799@gmail.com> wrote:
> > On Sun, Feb 15, 2009 at 9:48 PM, Bryan Christ <bryan.christ@gmail.com> 
wrote:
> >> I am writing a multi-threaded application which services hundreds of
> >> remote connections for data transfer.  Several instances of this
> >> program are run simultaneously.  The problem is that whenever the
> >> total number of active user connections (cumulative total of all open
> >> sockets tallied from all process instances) reaches about 700 the
>
> It seems that would be the same as setting RLIMIT_NOFILE via
> setrlimt() or the same as using the userspace tool "ulimit -n".  Am I
> wrong?  Isn't this the same?
>
> >> system appears to run out of file descriptors.  I have tried raising
> >> the open files limit via "ulimit -n" and by using the setrlimit()
> >> facility.  Neither of these seem to help.  I am currently having to
> >> limit the number of processes running on the system to 2 instances
> >> allowing no more than 256 connections each.
> >
> > Have you tried editing /etc/security/limits.conf  (or equivalent file
> > on your system) to increase the max number of open files?
> >
> > perhaps something like:
> > *              -       nofile         524288
> >
> > is what you want?
> >
> > joe

The solution used to be editing the kernel and tuning NR_OPEN and NR_FILE in

 /your/kernel/source/include/linux/fs.h

The kernel used to have an absolute hard limit that setrlimit and ulimit 
couldn't go past but I'm not sure if this has changed.

You could try bumping those up and recompiling or at least googling along 
those lines.