Re: XFS buffered sequential read performance low after kernel upgrade

Robert Brockway
2010-03-13T15:21:42Z

On Sat, 13 Mar 2010, Dave Chinner wrote:

> Also, the XFS partitions are on the inner edge of the disk, so they
> are always going to be slower (can be as low as half the speed) than
> partitions on the outer edge of the disk for sequential access...

Hi Dave. Hasn't it been the case for a long time that the sectors on the
HDD are no long necessarily numbered from the outside in? I understood
some HDD are numbered in the opposite direction and some are striped and
that HDD manufacturers tend not to release this info. Short of timing
tests I believe there is no easy easy way to figure out the sequence
anymore.

This has tended to nullify the old wisdom of putting the root filesystem
at the beginning of the disk[1].

[1] Which was done in the past because it was faster.

Cheers,

Rob

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