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From: David Miller <davem@davemloft.net>
Subject: Re: BTRFS partition usage...
Date: Tue, 12 Feb 2008 15:26:52 -0800 (PST)
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From: Jan Engelhardt <jengelh@computergmbh.de>
Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET)

> (Yes, I had xfs on sparc before, so it's not like you NEED the 
> whitespace at the start of a partition.)

You actully do unless you want to lose significant chunks of your disk
space.

The Sun disk label only allows you to specify the start of a partition
in cylinders, so if you want to use a filesystem like XFS you have to
start the partition on cylinder 1 which can be many blocks into the
disk.  That entire first cylinder is completely wasted.

What XFS does by putting the superblock at zero is simply does not
take these kinds of issues into consideration.