[Expectperl-discuss] Limit on number of Expect sessions?

[Richards, K. <Kei...@Co...>]

Hi,

I'd like to maintain a number of simultaneous ssh connections from one host
to maybe 300 others. I've been looking at using Perl Expect for this, and
it's been working well for small numbers of connections.

This script:

#!/usr/local/bin/perl -w
use Expect;
@exps = ();
for $i (1 .. 300) {
  print "$i\n";
  my $exp = new Expect;
  $exp->log_stdout(0);
  $exp->spawn("ssh gend51");
  my $match = $exp->expect(30, "gend51> ");
  push(@exps, $exp);
}

falls over when it hits 251, with the error:

Cannot open pipe: Illegal seek at
/usr/local/lib/perl5/site_perl/5.6.0/Expect.pm line 105.

I guess this is something to do with limited file descriptors, but I've
upped my fd limit (as reported by ulimit -n and limit descriptors) to 1024,
and no change.

I'm on Solaris 8, perl 5.6.0, Expect 1.15, 2GB RAM, 8GB swap.

Any thoughts about how to avoid the above problem?

Many thanks,

Keith.


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