Re: 9.0 beta2 & the new bsdinstaller

From: Peter Jeremy <peterjeremy_at_acm.org>
Date: Tue, 20 Sep 2011 16:23:49 +1000
On 2011-Sep-19 13:25:27 +0100, Bruce Cran <bruce_at_cran.org.uk> wrote:
>I seem to remember (perhaps incorrectly) there was a discussion about 
>bumping the default to 128 kB or more for the freebsd-boot partition. 
>Will 64 kB be enough for 9.x?

At least for x86 architectures, it seems adequate.  The GPT loaders
are 13K (UFS) and 33K (ZFS).  Even if they were combined with no code
overlap, that's only 46KB.  As for missing functionality, the only
things I can think of would be:
1) multiboot support - which is implemented in <<512 bytes for MBR so
it's difficult to see how it could require more than a few KB.
2) "nextboot" support for ZFS - writing to ZFS is not feasible in the
bootloader so this implies some other alternative.
3) Potentially linked to the above - provision for booting off ZFS
clones or snapshots.
I'm not sure how much code the latter two features might require.

As for size, I'd suggest that if the default freebsd-boot size is
going to be changed, it should be adjusted so that the following
partition is aligned to a reasonably sized power of 2 - 128KB or
256KB.

-- 
Peter Jeremy

Received on Tue Sep 20 2011 - 04:24:02 UTC

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