I'm currently attempting to re-architect a backup solution where I'm working.

We've got 2 NAS devices, one in the office, one in the datacentre. The servers in the DC back up to the DC NAS, which is then replicated to the Office NAS.

The office NAS exports shares as CIFS and NFS, this bit is fine. At some point, I'll have to expand our storage capacity, currently we've got about 1.4TB of storage space, which is about 96% full.

Previously, the tape backup was a script that ran tar a few times and squirted data onto a tape. It worked, but was by no means a perfect solution. Restores are a bit of a pest, adding new data to the backup requires editing the script as root.
It's just all a bit non-ideal.

I've been evaluating a number of "enterprise" ready backup solutions, such as Yosemite Backup from Barracuda, Acronis Backup/Restore, and something from Arkeia.

In the process of evaluating these, I've found 2 big problems.

1. Not all of them allow backup of mounted devices (such as a NFS mounted NAS)

2. Many of these applications don't like our tape device.

For the most part, (1) is essential. Our NAS has a feeble processor and can't run applications like backup agents.

I suspect that the biggest problem is the tape device, which is a HP C7438A DAT72 connected via USB.

Questions:

1. Has anyone else got an USB DAT72 device working with similar software?
2. Is there a better way to back up data from an "appliance" NAS device on which you can't run an agent?
3. Would I be totally out of my mind to specify a cheap HP or Dell server with a couple of 1TB hard disks, and a SAS card to then talk to an HP Ultrium (or similar) device? The biggest drawback to this would be cost (400ish for the server, 200 for the SAS connectivity and 1700 for a LTO4 device)

Notes:

I'd love to be able to say that I'd get rid of tapes entirely, and use some form of hard disk backup. In a previous job, we had LaCie USB drives, which were decidedly unreliable.