Small files perform much faster on newly formatted fs?

[Norbert Veber]

On Fri, Jun 10, 2011 at 07:17:31AM +1000, Dave Chinner wrote:
> The mount options are only there to cahnge the alignment that
> already exists, and there are significant limitations on those
> changes.

Oh I see.  I will reformat and set sunit/swidth for my current 3 disk
raid5 (2 data disks).  What if I later add a 4th disk (3 data disks),
would using the mount option to specify the new swidth have any
performance hit?  

I assume old files might work slower but any new data that is written
would be aligned across all the drives?  Or should I just reformat again
at that point?

Thanks,

Norbert