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Re: Status of Debian on Sun Blade 150



On Thursday 28 April 2005 02:35, Jurij Smakov wrote:
> On Thu, 28 Apr 2005, Wiktor Wandachowicz wrote:
> > Frans Pop wrote:
> >> With sun-disklabel you are not allowed to put swap or RAID or LVM at
> >> the start of the disk. ext2/ext3 are OK.
>
> Frans, if you are referring to #283303, I thought that we've fixed it.
> At least the bug is marked 'fixed' when version 62 of partman has been
> uploaded, and I remember testing it and confirming that the bug is
> gone. Version in RC3 is 63, so it should be fixed there too.

I've read through that bug and I think it is related, but does not cover 
the whole issue.
The basic problem AFAICT is that a linux swap partition does not treat the 
first sectors of a partition as special. I think that is reasonable as 
booting from a swap partition is, in general, nonsense. Ext2/3 _does_ 
reserve the first sectors of the partition for bootloader etc, so putting 
that at the start of the disk is OK.
See also the 2nd para under "DESCRIPTION" of silo(8) manpage.

Please read [1]:
- the 1st partition is required to start on sector 0;
- bootloader and disklabel info is written to the first sectors of
  the disk;
- _all sectors_ of a linux swap partition are used for swap and so
  may be overwritten when the partition is formatted or used.
Conclusion: don't put swap (or RAID or LVM) at the beginning of a Sun 
disklabel disk!

The logical thing to do is to put either the / partition or a small /boot 
partition at the start of a disk for Sparc systems.

This is also confirmed by the last postings to #283303. I think the patch 
in that bug only resolves some _symptoms_ of this issue, but does not 
address the real problem.

The MSDOS disklabel apparently automatically reserves the first sectors of 
a disk for the MBR, therefore having swap on the 1st partition of a MSDOS 
disc is not a problem.

[1] http://d-i.alioth.debian.org/manual/en.sparc/apbs05.html#id2538449

Cheers,
FJP

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