5.x separate /boot slice?

Garance A Drosehn gad at FreeBSD.org
Thu Aug 4 23:35:51 GMT 2005

At 12:56 AM +0300 8/5/05, Michael Dexter wrote:
>>>  I would like to try a separate /boot slice as permitted
>>>by FreeBSD 5.x...

I missed the beginning of this thread.  Where did you get the
impression that FreeBSD will work if you create /boot as a
separate partition?

>>Search the list.  This comes up about once a month, and I've
>>yet to see anyone succeed.

It came up on this very mailing list back on July 19th, with
the subject of:    'Re: /boot on a separate partition'

>>Aside from "it's the way Linux does it", do you have any good
>>reason for wanting this?
>All of my questions seem to generate that response. :) Trust me,
>they are informed questions. In short:

>I was thinking that previous and updated kernels could both coexist
>in /boot and a second root slice (plus usr ... as appropriate) could
>be mounted under /mnt and receive a fresh installation of the updated
>OS, rather than a overlay that requires mergemastering.  ....

>In some respects this is a question of dual-booting FreeBSD and
>FreeBSD and I was hoping to share some partitions that are not
>affected by the update process, likely including var and tmp.

But why does that shared partition have to be '/boot', and not '/'?
FreeBSD tends to have a small-ish '/' partition, and then have
separate partitions for /var and /usr, and often for /tmp.

I do exactly what you'd like to do, but the partition I duplicate
is '/'.  I have a '/' partition and a '/xRoot' partition, and I
use FreeBSD's snapshot feature (in 5.x and better) to duplicate
that partition into /xRoot.  This gives me a nice backup of
/boot, /root, and /etc.  I then upgrade the running system.  It
seems to work fine for me.  This is where we get back to the
question, "Why *must* your goal be done using a separate
partition for '/boot'?".

I do not mean that to be a hostile question.  I'm just saying
that I seem to be doing exactly what you want to do, and I've
never needed a separate /boot partition to do it.

The one trick involved is that you duplicate '/' to '/xRoot',
and then you have to remember to change '/xRoot/etc/fstab' so
that it points to itself as the '/' partition...  I do that
in a script, so that change is handled automatically...

Garance Alistair Drosehn     =      gad at gilead.netel.rpi.edu
Senior Systems Programmer               or   gad at FreeBSD.org
Rensselaer Polytechnic Institute;             Troy, NY;  USA

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