Suppose that you have a fully mirrored system and you want to expandyour available space by migrating to a pair of larger hard drives. Theobvious way to do this is fairly straightforward, assuming that youcan connect all of your drives at once: partition the new drives (withlarger partitions for at least some of your software RAID devices), addthe new partitions to the appropriate MD device, let things resync, andthen detach the old disks (and eventually physically remove them).

(Hopefully the obvious way

I was asked today if I thought that a disk-based backup system could do restores faster than a tape-based system. Mybest answer was a 'maybe', because it really depends on what thelimiting factor is in your restores. Let's look at all of the thingsthat have to happen in a restore:

1. you find and load the tape into the tape drive or tape library,if it's not already there.
2. if you have a tape library, it loads the tape into the

One of the slightly subtle advantages of disk-based backup systems over tape-based backup systems is thatcapacity expansion is much easier; all you have to do is start usingbigger disks. Since SATA is SATA, you don't need to replace yourenclosure, and it is relatively easy to have multiple generations ofdisks with different capacities cycling through your system.

Contrast this with tape backups. To upgrade to higher capacity tapes,you have to not just buy the tapes, you generally have to buy an entire