Mirror Drives
Note1 - Disks can be IDE, SATA, or SCSI.
Note2 - The 2nd drive must be the same size or larger for this to work.
Note3 - Start with no partition on 2nd drive.
Note4 - You will be making these disks dynamic, which requires 1mb of free space at the end of the disk.  If you created the partitions in Windows, no problem, but other utilities or OSs may not do this by default.

• In Disk Management, upgrade both disks to dynamic. (Requires 2 reboots - Does not take time for disks to change, only time for reboot)
• Right click disk0 and select Add Mirror. (Remember, disk1 needs to be unallocated space)
• You're done!
  

How to boot from the backup drive if the main mirror drive fails:

If you now want to boot from the new mirrored disk, you have to change the Boot.ini ARC path that points the computer to the partition in which the system files are located.

See "Booting From Mirror After Primary Partition Is Lost"
and "Steps to Recover a Failed Mirrored System/Boot Partition"

How to Resize Server Partitions
The best way to do this we have found is with Norton Ghost. Simply ghost the drive to a new one, and adjust the partians during the initiall setup for the process.