While I was searching for a backup solution to use on my new server, setup as follows:
1 - 160GB SATAII Internal Drive
1 - 1 Terabyte SATAII Internal Drive
1 - 1 Terabyte SATAII External Hard Drive via USB 2.0
I initially thought about running both drives internally and in a RAID 1 for redundancy. I was searching for this solution because I store all my important data (personal docs, music, movies, etc..) on this file server (just a Vista box which stays on all the time). RAID looked like it would be nice but I didn't fully trust the fake RAID which comes with many motherboards these days. The reason behind this is the inherent flaw in how RAID operates. If a corrupt file is created on one drive the same corrupt file will be place on both drives in a mirrored RAID setup - therefore your data integrity is still at risk. Also if something were to happen to the RAID parity or if the array crashed you would lost all data.
What I decided to do was use an external drive, and map the 1 Terabyte internal drive to all my home workstations. I then created a job which runs every 3 days which does a full incremental backup of the internal drive to the external drive. There is a separate job which runs every night which backups only a few important folders from the internal -> external such as folders containing frequently updated documents.
While looking for a solution which could do this (I assumed 3rd party software) I overlooked our new friend Robocopy. Robocopy is a new file copying command line program which comes installed with Vista and Win7. Robocopy has a feature/option called /PURGE what this will do is basically mirror everything from the source to the destination. This means that if you delete a folder in the source it will also delete it from the destination. This allows directory mirroring and incremental backups as Robocopy only copies non-same files from source to destination.
I use the following syntax in a batch file which is run via a scheduled task in Vista/Win7.
Robocopy S:\ E:\ /COPYALL /PURGE /R:0 /W:0
S: is my internal drive and E: my external. /COPYALL copies all file attribute info, /R stands for number of attempted file copy retries and /W provides the amount of time to wait before retrying.
Robocopy syntax: http://www.mydigitallife.info/2007/05/07/robocopy-syntax-command-line-switches-and-examples/