#...
use File::Find;
$File::Find::dont_use_nlink= 1; # Avoid slowing "optimization"
#...
my @dirs = qw(
    /nas/fs001 /nas/fs002 /nas/fs003 /nas/fs003
    /nas/fs004 /nas/fs005 /nas/fs006 /nas/fs007
    /nas/fs008 /nas/fs009 /nas/fs010 /nas/fs011
    /nas/fs012 /nas/fs013 /nas/fs014 );
#...
  my $dir = pop @_; # 1 arg only, because that lets me thread.
#...
       if ( -f _ && ! -l _ )
       {
         my $filesize = -s _;
#...