Isilon Protection Levels

Hi All,

Quick question.  Isilon Protection Levels.  If a cluster is set to 2d:1n, does that mean if a disk smartfails and is waiting to be replaced, that you can only lose another disk?  Or does it mean that the data on the disk that has smartfailed has been restriped on other disks, so I can lose another 2?  I just need to get this clear in my head.

Thank you.