Hmm... I thought the question was about terabytes of media files.
In a previous thread (http://yabb.jriver.com/interact/index.php?topic=30723.0) you listed some of the things that you do for backup. Would you mind listing the complete process? I'm very interested in what software you use and if your incremental backups come from new files or files that also have had tag changes? How much is automated? You take a lot of consideration with tagging/filing etc., so I wanted to get your opinion/system on backups too.
This has been discussed a couple of times before and the forum users have explained some good ways to do it. You could search for the older threads and bump one of them.
Basically it is nothing very complicated. A good backup tool can keep two separate drives or base folders synchronized and copy or remove only the needed files. I have used
Dantz's Retrospect since I have had it for ages, but for example
Two Bright Sparks has very good tools. Their basic version is freeware and it is enough for many users.
My MC server PC has 500 GB of internal HD space. From day to day I update the first backup drive pair. I have split the backup data on two separate Firewire/USB2 drives (250 + 250 GB), but easier would be to have one big enough drive. I keep the other pair in a safe place and I exchange the drive pairs weekly or so. The newest files in my safe place are never older than a bit over one week. I hope that in the worst case I would have at least those files.
Also, I have several tray mounted removable hard drives that I use for offline storage - mainly for the lossless Audio CD image files (currently about 800 GB plus another 800 GB for the backups). I have not bothered to make two separate backups of these because the drives are powered very rarely.
My boot and software partition is about 50 GB and I use
Acronis True Image and some old smaller HDs for making bootable drive images of it. These I connect directly to the HD connectors inside the PC when needed.
So I have 1.5 TB for the online files (including the two backups) and over 1.6 TB for the offline files. Unfortunately all drives all almost full at the moment. I need to increase the storage space again sometime soon.