The parameter server_key is very confusing, it's not a server key for MemCached Server, but it's key,in key-value pair which you stored in server.
<?php
$m = new Memcached;
$m->addServers(array(
array('127.0.0.1',11212),
array('127.0.0.1',11211)
));
for($i=0;$i<10;$i++){
$key = 'key_'.$i;
$m->add($key, 1);
}
for($i=0;$i<10;$i++) {
$key = 'key_'.$i;
$arr = $m->getServerByKey($key);
echo ($key.":\t".$arr['port']."\n");
}
?>
key_0: 11212
key_1: 11211
key_2: 11212
key_3: 11212
key_4: 11212
key_5: 11211
key_6: 11211
key_7: 11212
key_8: 11212
key_9: 11211
