use strict;
use XML::Rules;

my %conf_of;
my $parser = XML::Rules->new(
	stripspaces => 7,
	rules => [
		'_default' => 'content',
		'Device' => sub {
			$conf_of{$_[1]->{Dev_Info}{dev_name}} = "$_[1]->{Dev_Info}{configuration},$_[1]->{Capacity}{cylinders}";
			return;
		},
		'Dev_Info,Capacity' => 'no content',
	],
	start_rules => [
		'Hyper,RAID-5_Device,Back_End,Mirror_Set,Front_End,Product,Label,Flags' => 'skip',
	],
);

$parser->parse(\*DATA);
use Data::Dumper;
print Dumper(\%conf_of);

__DATA__
<?xml version="1.0" standalone="yes" ?>
<SymCLI_ML>
...