I'm looking at an rsnapshot backup situation, and rather than buying a
big chunk of high-speed, expensive, server class storage, I'm
wondering about simply using external USB's and buying several. It's
clearly technically feasible: I've been doing so for months, for FTP
mirror material.

Has anyone done it in a vaguely high performance configuration?
Updating about 200 GB of new database material daily, and backing it
up to tape? How is the transfer speed on a modest, 2 GHz, 1 GB of RAM
server with normal USB 2.0 and a normal tape drive, such as an SDLT
800?

In fact, if anyone has typical performance specs with plain old tar,
or Amanda, for SDLT 800's, I'd very much appreciate that information
as well.

Nico Kadel-Garcia