[Chadi]

Yes to both questions.

//$config['Datastore']['class'] = 'vB_Datastore_Memcached';

    // ******** DATASTORE PREFIX ******
    // If you are using a PHP Caching system (APC, XCache, eAccelerator) with more
    // than one set of forums installed on your host, you *may* need to use a prefix
    // so that they do not try to use the same variable within the cache.
    // This works in a similar manner to the database table prefix.
// $config['Datastore']['prefix'] = '';

    // It is also necessary to specify the hostname or IP address and the port the server is listening on

$config['Datastore']['class'] = 'vB_Datastore_Memcached';
$i = 0;
// First Server
$i++;
$config['Misc']['memcacheserver'][$i]        = '127.0.0.1';
$config['Misc']['memcacheport'][$i]            = 11211;
$config['Misc']['memcachepersistent'][$i]    = true;
$config['Misc']['memcacheweight'][$i]        = 1;
$config['Misc']['memcachetimeout'][$i]        = 1;
$config['Misc']['memcacheretry_interval'][$i] = 15;

// ****** The following options are only needed in special cases ******

    //    ****** MySQLI OPTIONS *****

root@server [~]# ps aux | grep memcache
root      6140  0.0  0.0  5316  736 pts/0    S+   18:22   0:00 grep memcache
nobody   27945  0.0  0.0  2896  836 ?        Ss   16:06   0:00 /usr/local/bin/memcached -u nobody -d -m 2048 -l 127.0.0.1 -p 11211


root@server [~]# ps aux | grep memcached
root      6150  0.0  0.0  4156  736 pts/0    S+   18:22   0:00 grep memcached
nobody   27945  0.0  0.0  2896  836 ?        Ss   16:06   0:00 /usr/local/bin/memcached -u nobody -d -m 2048 -l 127.0.0.1 -p 11211