We have just found a failing hard drive on node 21 Phoenix, which will be replaced shortly.
As always, no data has been lost, but we have temporarily taken down the system until further notice. Once the drive has been replaced, we will bring the node back up (within the next 1-2 hours).
We apologize for any inconvenience that this may cause.
Update: The drive has been replaced and the servers on the node are back online.