This is probably closer to what you are looking for.
It can handle multiple devices, and multiple occurrences of different errors for each device. 
#!/usr/bin/perl
use warnings;
use strict;

my %devinfo;

while (<DATA>) {
  next unless my ($date,$time, $device, $err) = /(\w+ \d+) ([\d:]+)\s(
+\S+) \[[^\]]+\]([^\(]+)\s?\(\d+/;
  $devinfo{$device}{$err}{COUNT}++;
  $devinfo{$device}{$err}{FIRST_TIME} ||= [$date, $time];
}

for my $dev (sort keys %devinfo) {

    print "DEVICE\t--> $dev ==============\n";
    for my $err (keys %{ $devinfo{$dev} }) {
      my $errinfo = $devinfo{$dev}{$err};
      print "DATE\t--> $errinfo->{FIRST_TIME}[0]\n";
      print "TIME\t--> $errinfo->{FIRST_TIME}[1]\n";
      print "ERROR\t--> $err\n";
      print "\nThe above error occurred $errinfo->{COUNT} times\n\n";
   }
}
__DATA__
<put data here>

[download]
Output, with your data: 
DEVICE    --> esw001tff2 ==============
DATE    --> Oct 17
TIME    --> 10:35:43
ERROR    --> Server reset. Occurred 1 time. 

The above error occurred 2 times

DATE    --> Oct 17
TIME    --> 10:35:39
ERROR    --> IP Spoofing from 255.255.255.255 to 255.255.255.255! Occu
+rred 1 time. 

The above error occurred 7 times

DATE    --> Oct 17
TIME    --> 10:35:47
ERROR    --> Root login failure! Occurred 1 time. 

The above error occurred 3 times

[download]

             "By three methods we may learn wisdom: First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest."           -Confucius

In reply to Re: Counting keys in a hash by NetWallah
in thread Counting keys in a hash by cspctec

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