[mdlug] Create an XFS file system in freespace

[Jonathan Billings]

On Wed, Jul 16, 2008 at 11:38:10PM -0400, Robert Meier wrote:
> It is analagous to a big file stored in the primary partition and
> mounted loopback.
> If the primary partition (or table entry) is damaged,
> you probably lose the extended partition, 
>
> It differs from a loopack file,
> in that the parent "filesystem" data is read only once,
> at mount-time, rather than potentially at each disk access.
> This shaves a few microseconds off each disk access,
> at the cost of potentially more disk fragmentation.

What?  This is just confusing.  An extended partition is just an
extension to the original MSDOS partition label, that lets you create
logical partitions inside a primary partition.  The partition layout
typically is read during boot for ALL partitions, including primary
partitions.  Filesystem fragmentation has nothing to do with partition
layout.

When linux boots, it reads the partition layout and maps devices to
the start and end of the partitions, both primary and extended.  There
is no 'cost' for using an extended partition other than that fraction
of a second extra it takes to decode the logical partitions during
boot.  

-- 
Jonathan Billings <billings at negate.org>