This server will be going down for about on 90mins on the above date to do some significant disk rearrangement. I'm pulling the existing mirrors and installing a pair of 250GB SATA drives to completely mirror the entire system. However, this will take a little bit of time to install the new drives, resync the disks and verify operation.
[Edit: shrunk window as I have most of the mirror in place already, I just need to sync up 12 hours of changes and install the new drives]