I've come to the conclusion that taper has no knowledge of (or
at least pays no attention to) tapelength.
  While modifying my disklist to back up more data from a local
rsynced copy of remote hosts rather than directly from the remote
host, I accidently ended up backing up a lot of the data twice,
causing a normally single tape config to consume 3 tapes.
  The config uses 100GB tapes, software compression only, and
plenty of holdingdisk so that nothing goes direct to tape.  My
tapelength is set to 98GB (determined through trial and error,
the earliest it has ever hit EOT was at 98.6GB).
  From this last run:
Output Size (meg)      194859.3   194859.3        0.0

taper: tape archive19 kb 98729312 fm 9 writing file: No space left on device
taper: retrying p143:/.0 on new tape: [writing file: No space left on device]
taper: tape archive20 kb 99180736 fm 86 writing file: No space left on device
taper: retrying q47:/remote.0 on new tape: [writing file: No space left on 
device]
taper: tape archive01 kb 43443680 fm 2 [OK]

So Amanda wrote over 240GB trying to write 195GB of data, and hit EOT
twice at a size past what I specified the tapelength as, so quite a
bit of time was wasted writing 45 GB of date to tape when it should
have known it wasn't going to fit anyway and would have to write it again.
   I know that planner does a good job of not scheduling more than
tapelength * runtapes, but shouldn't taper also keep track of how
much is written and skip to the next tape if the next DLE won't fit?
   Also, is the taperalgo variable apply per tape or per run?  I
have mine set to largestfit, but that didn't seem to have any effect.
I'm guessing it only applies to whatever is curently ready to be
taped and not all remaining DLEs.  Is there a way to tell Amanda
to delay taper until after all dumpers finish before writing to
tape. This would require holdingdisk > total dumps but would
allow most efficient use of tape, assuming it paid attention to it.

Frank

-- 
Frank Smith                                      fsmith AT hoovers DOT com
Sr. Systems Administrator                       Voice: 512-374-4673
Hoover's Online                                   Fax: 512-374-4501