On Thu, Jan 04, 2018 at 08:59:32PM -0500, Ned Danieley wrote:
> On Thu, Jan 04, 2018 at 05:16:59PM -0700, Steven Backus wrote:
> > Ned Danieley <ned.danie...@duke.edu> wrote:
> >
> > > ah, that makes sense. no, I haven't run 'amtapetype'; I just assumed that
> > > the rated capacity would be accurate. I'll give it a try; in the meantime,
> > > has anyone run 'amtapetype' on an LTO6 tape? I have an HP Ultrium 6 drive.
> >
> > I did and got:
> >
> > define tapetype LTO6 {
> > comment "Created by amtapetype; compression disabled"
> > length 2442954880 kbytes
> > filemark 7456397 kbytes
> > speed 154519 kps
> > blocksize 32 kbytes
> > }
>
> thanks. that fairly well matches what I was using
>
> define tapetype LTO6comp {
> length 2443520000 kbytes
> filemark 868 kbytes
> speed 157129 kps
> blocksize 2048 kbytes
> }
>
> except for filemark; can anyone comment on that? looking at the tapetype
> definitions on the zmanda wiki, it seems that most of the LTO entries have
> zero kbytes for filemark...
>
It is the space (if any) left between files written to the tape.
Suppose you write a continuous stream of data to a tape
and you can write exactly 100GB. If no space was left
between files you should be able to write 100 x 1GB files.
When you try it (as amtapetype does) and you find you can
only write 98 x 1GB files, 2GB was used by "filemarks".
Divide 2GB/98 files and you have your filemark.
I believe Amanda does consider filemarks in its determination
of what will fit on a tape.
jl
--
Jon H. LaBadie j...@jgcomp.com
11226 South Shore Rd. (703) 787-0688 (H)
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