On Jul 14, 2011, at 7:56 PM, Ken Mandelberg wrote:

Under Legato the license restriction artificially keep the "file-device" 
small relative to the tape storage. However, these days disks are 
cheaper than tapes and license free we could afford a lot of disk space.

I know hard drives are cheap these days, but I didn't realise they were cheaper than tape nowadays.  LTO-4 media works out at less than 5 cents per GB (uncompressed) last time I bought it, and I believe LTO-5 is less than 4 cents per GB (again, uncompressed).

But, don't underestimate some of the perhaps-neglected advantages of tape:

- Easier to offsite for long-term archiving and disaster recovery
- WORM capability for regulatory compliance where needed
- Easier to expand total capacity---just buy more media
- Increasing capacity doesn't continually eat up rack space and drive up power consumption

Personally, I like the fact that Bacula supports a mixed disk/tape solution, allowing for disk to provide faster near-line access to more recent backups (e.g., incrementals) and tape for older material.