(PECL mongo >=1.5.0)
MongoClient::setWriteConcern — Set the write concern for this connection
wThe write concern. This may be an integer denoting the number of servers required to acknowledge the write, or a string mode (e.g. "majority").
wtimeoutThe maximum number of milliseconds to wait for the server to satisfy the write concern.
Returns TRUE on success, or FALSE otherwise.
Emits E_WARNING if the w parameter is not an integer or string value.
Example #1 MongoClient::setWriteConcern() example
<?php
$mc = new MongoClient('mongodb://rs1.example.com,rs2.example.com');
// Require that the majority of servers in the replica set acknowledge writes
// within three seconds.
$mc->setWriteConcern('majority', 3000);
?>