APC usage by vhost (for Plesk)

apc_usage.php

<?php

$apc_entries = apc_cache_info();
$apc_entries = $apc_entries['cache_list'];

$usage_data = array();

foreach ($apc_entries as $entry) {
    
    $filename = $entry['filename'];
    $num_hits = $entry['num_hits'];
    $mem_size = $entry['mem_size'];

    $slices = '';
    if (preg_match('/\/var\/www\/vhosts\/([a-z\.]+)\/.*/i', $filename, $slices)) {
        $vhost = $slices[1];

        if (!isset($usage_data[$vhost])) {
            $usage_data[$vhost] = array(  
                'hits'     => 0,
                'mem_size' => 0,
                'load'     => 0
            );
        }
        
        $usage_data[$vhost]['hits'] += $num_hits;
        $usage_data[$vhost]['mem_size'] += $mem_size;

        //This metric approximates RAM usage
        $usage_data[$vhost]['load'] += $num_hits * $mem_size;
    }
}

print_r($usage_data);

Yes, it's a print_r() at the end. It's up to you what you do with that data. Personally, I send it to Datadog ;-)