use strict;
use Data::Dumper;

my %backups;

while (<DATA>)
{
   next if (/^\s*$/);    #skip blank lines
   chomp;
   
   my ($date, $backupset , $parm , $value) = parseline($_);
   
   if ($value)
   {
      $backups{$backupset}{$parm} = $value;
   }   
}

print Dumper \%backups;

sub parseline
{
   my $line = shift;
   my ($date, $rest) = $line =~ m/(^.*\d{4}):(.*)/;
   my ($backupset,  $msg) = split(/backup:INFO:/, $rest);
   $backupset =~ s/:\s*$//;  #trim some unwanted thing like ':' is ok
   $backupset =~ s/^\s*backup\.//; #more than one step is just fine!
   my ($parm, $value) = $msg =~ m/\s*(.*)=\s*(.*)\s*/;

   $parm  ||= $msg;   #if match doesn't happen these will be undef
   $value ||="";      #this trick makes sure that they are defined.

   return ($date, $backupset, $parm, $value);
}   

=print
#some reformatting to try to stop line wrap....
$VAR1 = {
          'set1_lvm' => {
 'backup-size' => '187.24 GB',
 'backup-set' => 'backup.set1_lvm',
 'backup-time' => '01:59:04',
 'backup-date-epoch' => '1281942003',
 'backup-status' => 'Backup succeeded',
 'last-backup' => '/home/backups/backup.set1_lvm/20100815000006',
 'backup-type' => 'regular',
 'backup-date' => '20100816000003'
                        },
          'set2_lvm_lvm' => {
  'backup-size' => '424.53 GB',
  'backup-time' => '04:33:12',
  'backup-status' => 'Backup succeeded',
  'last-backup' => '/home/backups/backup.set2_lvm_lvm/20100814200003'
                            },
          'set2_lvm' => {
  'backup-directory' => '/home/backups/backup.set2_lvm/20100815200003',
  'backup-set' => 'backup.set2_lvm',
  'backup-date-epoch' => '1281927603',
  'backup-type' => 'regular',
  'backup-date' => '20100815200003'
                        }
        };
=cut
__DATA__
Sun Aug 15 20:00:03 2010: backup.set2_lvm:backup:INFO: START OF BACKUP
Sun Aug 15 20:00:04 2010: backup.set2_lvm:backup:INFO: backup-set=backup.set2_lvm
Sun Aug 15 20:00:04 2010: backup.set2_lvm:backup:INFO: backup-date=20100815200003
.....
use __DATA__ segment from my previous post