Small files perform much faster on newly formatted fs?

[Christoph Hellwig]

On Thu, Jun 09, 2011 at 11:29:07AM +1000, Dave Chinner wrote:
> > > Then retry mounting the old fs with sunit= and swidth= parameters. Are 
> > > they on the same disks? What are your disks (number, kind)?
> > 
> > Yes its already mounted this way as I mentioned in my original message:
> > /dev/mapper/vg0-shared on /shared type xfs (rw,noatime,sunit=128,swidth=256)
> 
> Those mount options are ignored if the filesystem doesn't have the
> superblock feature bit set for aligned allocations. A filesystem
> with 0/0 for sunit/swidth does not have the superblock bit set....

The other thing that sticks out is the lack of lazy-count for the old
filesystem.  That will give a lot of additional superblock updates on
the old one.