Comment Home Server 2003 (Score 1) 2
Home server 2003 does real time replication. Check out this screen shot, and note the "duplication" column:
http://www.connectedinternet.co.uk/wp-content/uploads/shared-folders.png
All you have to do is install Home Server with two or more drives, and check [x] enable duplication for the shared folders you want to replicate. It's that easy. If one of the duplicated drives fails, the data is on the other drive in NTFS format. This means that you don't have to rebuild a RAID array. I ripped my audio collection about 10 years ago, and I have been running Home Server for about 6 years now. It has successfully duplicated 8TB of data without issue during that time.