Degraded Raid on Xserve Software Raid

Hi, our xserve has a degraded raid pair - [img]http://www.grabup.com/uploads/3547ed1983bb341394585828b434eaf1.png[/img] What are my options? Can I simply remove the failed drive, add a new one to the mirror and it'll all be ok? Can I do this whilst the server is online?