Date: Tue, 4 Mar 1997 14:31:36 -0600 (CST) From: "Paul T. Root" <proot@horton.iaces.com> To: dwhite@resnet.uoregon.edu Cc: bartol@salk.edu, questions@freebsd.org Subject: Re: Density codes for Exabyte 8505XL Message-ID: <199703042031.OAA01300@horton.iaces.com> In-Reply-To: <Pine.BSI.3.94.970304104546.21914I-100000@localhost> from Doug White at "Mar 4, 97 11:03:43 am"
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In a previous message, Doug White said:
> On Mon, 3 Mar 1997, Tom Bartol wrote:
>
> >
> > Thanks for the info. The -B and -b options for dump are new to me and are
> > most interesting but not exactly what I was after. An 8505XL can read and
> > write in four density modes: 2.6 GB, 5 GB, 7 GB, and 14 GB (all on a 112
> > meter tape). I'd like to use the 14 GB mode. One can use the mt command
> > to set the density mode but it's not clear what density code to use to get
> > this mode.
>
> Ah, I understand. As I said, I'm not familiar with the Exabyte tapes.
> You might poke the mail archives if you haven't already, someone may
> have it your problem before.
>
> > After having set the mode to 14 GB, though, the -B and -b dump
> > options (set to say, 450000 and 32 respectively) would be extremely useful
> > to allow dump to calculate how many tapes it will need and its progress
> > etc... I assume you meant to say you use -B = 200000 not 2000000 in your
> > example below -- 200000 * 10K = ~2GB.
>
> Well, that is what those options are for :) I'm aware the values are
> wrong, but for some reason the tape estimates check out if we use those
> values. It's not a big deal, we don't have even close to 2gb of data to
> backup, and the guy who does the backups insists on using separate tapes
> for each machine and we don't do incrementals. Our backup strategy is
> "lacking" to say the least, but it's not the end of the world if the disks
> blow up.
Doug, get amanda, its wonderful.
Tom,
As far as accessing the density modes, seems to me that you change modes
via ioctl's therefore, you won't be able to change that via options on
dump. Seems to me you'd need to access them via different devices. Solaris
does it like:
/dev/rmt/0 - regular density
/dev/rmt/0h - high density.
etc.
Oh, looking in /dev/MAKEDEV, and /dev you'll see /dev/rst0.[0123]. Maybe that's
it. The MAKEDEV calls it rst${unit}.${mode}. I'd bet that that's what
you want.
Do a man st. Hopefully, that will have ethe answer your looking for.
--
What does a blonde say after six years of college?
--"Welcome to McDonald's... would you like to try the combo meal?"
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