> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of
> Dustin J. Mitchell
> Sent: Wednesday, July 07, 2010 1:14 AM
> To: McGraw, Robert P
> Cc: [email protected]
> Subject: Re: Tape Usage Question
>
>
> On Tue, Jul 6, 2010 at 11:56 PM, McGraw, Robert P <[email protected]>
> wrote:
> > In my case there were several dump image that could have been written
> to the tape. Amanda did not seem to pick the largest dump image that
> would fit on the tape.
>
> Well, bear in mind that the tape drive does not give any indication of
> space left -- all Amanda has to go on is dead reckoning based on the
> parameters in the tapetype and what it has written so far. So if
> Amanda chose the 37GB dump, it probably expected at least 37GB
> remained on tape at that point, although you knew better. Are your
> tapetype parameters correct?
>
> Dustin
>
> --
> Open Source Storage Engineer
> http://www.zmanda.com
[McGraw, Robert P]
Dustin,
I use an LTO-2 drive which is supposed to give 200GB uncompressed and 400GB
compressed. I realize that the 400GB is the absolute max and would never be
obtainable. So I make tapetype equal to a pretend 350GB which seems to be a
good number. So to amanda it thinks that the tape size is 350GB and bases it
calculations on this number.
define tapetype LTO2-HWC {
comment "LTO-2-Hardware Compression on."
blocksize 1024 kbytes
length 350000 mbytes #350G compressed
filemark 0 kbytes
speed 27315 kps #27 Mb/s
}
The problem is not the size of the physical tape, the problem is that amanda
did not pick the largestfit dump image based what amanda knew to be how much
was left on the tape based on tapetype length size of 350GB.
1) amanda knows the tape size based on tapetype information which in my case is
350GB.
2) amanda knows the amount of data the is written to tape. You can see that in
the amreports and amstatus information.
3) amanda knows how much disk spaced is left of the 350GB and from this number
amanda should get the largestfit dump image that is less than the disk space
left. In my case amanda picked a dump image that was bigger that the disk space
left. So as the templar knight said in the Indiana Jones "The Last Crusade"
amanda "did not pick well".
Oh well I do not want to beat a dead horse.
Thanks
Robert
