[Posted and Cc'ed]

On Wed, Jan 15, 2003 at 04:32:23PM -0500, Eric Sproul wrote:
> After disabling H/W compression, I am getting the same performance from
> tapetype.  It has been running for 15 hours and has only written about
> 30GB.

There is >1 tapetype version around, it's got command-line options,
there are ways to go wrong.

> What are the consequences of having the wrong values in a tapetype
> definition?  If the size value is too large, Amanda will just encounter
> EOT sooner than expected, right?  If it's too low, you waste some tape. 
> I'm thinking I might take what people have already posted for the DLT220
> drive and scale it up by 45% (160 is 45% more than 110).  Am I crazy? 

Not crazy at all.  I think folks get a little too hung up on tapetype.
With your drive, for example, it's hard to see how you would give
a darn *what* filemark is, unless your disklist is >1000 entries
long...

However, you bought yourself a big, fast drive, and what you *should*
do is to confirm that it *is* big and fast.

Make yourself a "representative" disk file (15GB of gzipped tar file,
80GB of uncompressed xfsdump file, whatever is apprpropriate for *your*
Amanda environment).  Run a loop on it like this (pardon the csh, it
was a 60-second quickie):

#!/bin/tcsh -f
set count=1
while (1)
    echo transfer $count
    time dd if=/a6/backup/spitfire._a1.20020718.0 of=/dev/rmt/1cn obs=32k || 
exit
    @ count++
end

Always good to be a little conservative on length, particularly if
runtapes=1; you don't want Amanda to estimate a run that doesn't end up
fitting.

-- 
Jay Lessert                               jay_lessert AT accelerant DOT net
Accelerant Networks Inc.                       (voice)1.503.439.3461
Beaverton OR, USA                                (fax)1.503.466.9472