Amanda writes data to tape as quickly as the tape drive will allow.
The tapespeed is not currently used.

The data may be in local cache, explaining some of the high speed.  I
don't know SATA-1 rates off the top of my head to know if that's too
fast.

Whatever goes on, data corruption should not result.  I'm interested
to hear what sort of corruption you're seeing.

Dustin

-- 
Storage Software Engineer
http://www.zmanda.com