Re: Boot Drive Nomenclature and How to Figure it out
On Fri, Sep 3, 2010 at 9:10 AM, Martin McCormick mar...@dc.cis.okstate.eduwrote: I have been writing a script to build a system from a mfsboot startup and it is going well but I want to revisit part of the script that I don't think I did a very good job with. Is there an automatic way to tell which of the devices shown in /dev is a likely system drive? This is before anything is mounted. We can usually figure it out ourselves, but is there a way for a script to figure out automatically which character device could be the one we are going to put the OS on and use as our boot drive? I know this sounds really obvious and you can tell scripts not to use /dev/acdx as they are CDROM devices, but system drives can actually take many different names depending on whether they are RAIDs SCSI IDE, etc. Any good suggestions are appreciated. Would doing something like: gpart list help? -- Adam Vande More ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Boot Drive Nomenclature and How to Figure it out
Adam Vande More writes: Would doing something like: gpart list help? Thank you. I have never heard of gpart before so I gave it a try and that helps very much if the drive is already formatted. Most of these drives I plan to encounter will be formatted so this basically solves the problem but it raises a new question. If one does gpart list as suggested and the disk is formatted, one gets exactly the information necessary. I believe it is even the first line of output. It doesn't get better than that. If the disk is not corrected formatted such as might happen with corruption or maybe a new drive, gpart list executes silently and prints nothing on the output. As I said, you answered my question so many thanks. The new question might best be put: Okay, if nothing is there, where did gpart look to see nothing? Martin McCormick ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Boot Drive Nomenclature and How to Figure it out
On Fri, Sep 3, 2010 at 10:04 AM, Martin McCormick
mar...@x.it.okstate.eduwrote:
Thank you. I have never heard of gpart before so I gave
it a try and that helps very much if the drive is already
formatted. Most of these drives I plan to encounter will be
formatted so this basically solves the problem but it raises a
new question. If one does
gpart list as suggested and the disk is formatted, one gets
exactly the information necessary. I believe it is even the
first line of output. It doesn't get better than that. If the
disk is not corrected formatted such as might happen with
corruption or maybe a new drive, gpart list executes silently
and prints nothing on the output.
As I said, you answered my question so many thanks. The
new question might best be put:
Okay, if nothing is there, where did gpart look to see nothing?
I believe gpart checks the geom sector which the last one of a particular
geom class. The sector is written anytime the geom device is added or
updated. This applies only to geom devices which are hardcoded. For
example, /dev/ad0 and /dev/ad0p1 would both be seperate geom classes and
have their own meta-data sector.
FWIW, the only suitable hard disk devices I know of are:
/dev/ad{0-9}
/dev/ada{0-9}
/dev/da{0-9}
If you're writing a test, I would probably grep dmesg for the presence of
one of them. The first device appearance is probably a prime candidate for
installation target.
--
Adam Vande More
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