XFS journaling position

[Robert Brockway]

On Wed, 27 Oct 2010, Michael Monnerie wrote:

> in an area where disks are slower than on the outside. And if you fill
> only half of the partition, it means your log is totally on the end of
> the disk, access-wise.

Hi Michael.  Ignoring LVM for a moment...

My understanding is that the relationship between the physical cylinders 
and the logical cylinders software see is no longer necessarily linear - 
ie, the lower number logical cylinders aren't necessarily at the outer 
edge.

This article talks about this:

http://lissot.net/partition/mapping.html

Unless you know the underlying physical cylinder layout you can't reliably 
position the journal in the middle cylinder on the physical media.

I understand the disk drive manufacters aren't necessarily forthcoming 
with the necessary information although it could be established from 
timing tests.

Cheers,

Rob

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