Hi I am trying to organise a proper backup system for the server here. We have ~100gb of data that needs to be backed up, so would it be possible to fit a full backup and 4-5 incremental backups on one 500gb hard drive? (Full backup = 100gb, but differential backups smaller?) Ed
You don't say if your server is Windows or Linux. For Linux http://www.nongnu.org/rdiff-backup/ works quite well, it holds one full backup plus a set of differentials for the history you require. If you are going to have more servers and can justify the cost then http://www.r1soft.com is worth a look.
You should use 750 GB hard drive. Here, you should keep the monthly, weekly and daily backups. You can also use 5 incremental daily backups.
I would also recommend looking at ZFS (currently used by Solaris and Mac OS X as their default filesystem) which allows you to make full filesystem snapshots that only take up as much room as an incremental snapshot and also compresses all files saved on the disk on-the-fly. (Thanks to CPU growing so much these days and disk speed not growing much, this results in disk access being much faster on ZFS than other filesystems.) ZFS is what makes Apple's Time Machine work.