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Date: Wed, 29 Apr 2009 10:34:57 +0300
From: Andriy Gapon <avg@icyb.net.ua>
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To: Ivan Voras <ivoras@freebsd.org>
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Cc: freebsd-stable@freebsd.org, freebsd-geom@freebsd.org
Subject: Re: fsck, glabel and sudden parallelism
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on 28/04/2009 14:34 Ivan Voras said the following:
> Andriy Gapon wrote:
>> So I recently switched one system to have only (g)labels instead of "raw" device
>> names in fstab and noticed that now initial (preen) fsck is performed in parallel
>> on couple of filesystems where before it used to be sequential.
>>
>> Here is a lengthy quote from fsck(8):
[snip]
>>> The disk drive containing each file system is inferred from the shortest
>>> prefix of the device name that ends in a digit; the remaining characters
>>> are assumed to be the partition and slice designators.
>> I think it is highly desirable that fsck knows which filesystems reside on the
>> same disk regardless of how they are referred to.
>> I think that the simple string matching described above is not sufficient these days.
>> Is there an easy geom way to query this info?
> 
> Yes, contents of kern.geom.confxml could be used to walk the tree of
> GEOM devices and find what drive they are physically on.

It seems that the less interesting part is already done - geom_gettree()
from libgeom, the more interesting part is some logic for directed graph
(geom "mesh") navigation.

Marcel,
I seem to recall that there was a conversation about making fsck more
geom aware (it was in context of inferring fs type from disklabel). Do
you have any work in progress in this area?

-- 
Andriy Gapon