in reply to scp cronjob

My best guess is that the $list file is getting over-written by multiple copies of the Perl script, when your bandwidth limits cause one copy to hang long enough for another copy to start.

Here are some other thoughts:

  • You don't need the $list file. Use backticks instead:
    @backupFiles = `ssh user\@backupserver ls /usr/local/apache/htdocs`;

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  • You are using File::Find and "globbing" (</path/*.htm>) together. This is redundant; use one or the other.
  • Do you really want to back up only the new files, but not any changed files? This confuses me.
  • ls -c is an odd command for this program; you are asking ls to sort by ctime, then throwing away the sort order by using a hash. Plain ls would be clearer.
  • Rather than use cron, you might just have the Perl script run as a daemon, never ending until you kill it. This would prevent the multi-copy problem, too.
    while (1) {
  do_something();
  sleep 60;
}

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  • If bandwidth is a problem, keep a flagfile whoses modtime is equal to the time of the last scp transfer. If no local file is newer than the flagfile, you can skip the ssh traffic.
  • You are calling scp once for each file; instead, you could build a list of files and call scp once:
    my @files = map { "'$_'" }
            grep {not $chompedList{basename($_)}
            </usr/myfiles/*.htm>;
system "scp -C @files user\@backupserver:/usr/local/apache/htdocs";

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  • You are using fileparse where basename would be clearer.
  • Finally, listen to ides. Rsync was designed for this kind of job. It has lots of options to fine-tune what gets synced and how; it can even limit its bandwidth use. Rsync should work great by itself as a cron job, but here is a (lightly tested) script to demonstrate my other points: 
    #!/usr/bin/perl -W
use warnings 'all';
use strict;

my $rmthost  = 'backupserver';
my $rmtuser  = 'user';
my $rmtpath  = '/usr/local/apache/htdocs';
my $lclpath  = '/usr/myfiles';
my $lclglob  = '*.htm';
my $flagfile = '.last_backup';
my $r_opts   = "-azq --blocking-io -e 'ssh -l $rmtuser'";
my $lclfiles = "$lclpath/$lclglob";

sub modtime {
  my $file  = shift;
  my @stats = stat $file or return 0;
  return $stats[9];
}

while (1) {
  my $timestamp = modtime("$lclpath/$flagfile");
  my $run = grep {modtime($_) > $timestamp} glob $lclfiles;
  if ($run) {
    system "rsync $r_opts $lclfiles $rmthost:$rmtpath";
    open  FLAG, ">$lclpath/$flagfile" or die;
    close FLAG or die;
  }
  sleep 60;
}

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