> It might be an interesting experiment to build a file 
> system consisting of a single cylinder group and measure its 
> performance.  

Because of the limitation that all the allocation bitmaps be in a
single filesystem block, the maximum size of a cylinder group is
(about) 45MB with 8k blocks.

This causes large disks to have a stupidly large number of cylinder
groups (and hence alternate superblocks).

NetBSD's current newfs creates a filessytem where each cylinder group 
only contains a single cylinder.  This means that you don't have to
have per cylinder information lurking which seriously restricts the
cylinders per cylinder group with traditional ffs filesystems.

ffsv2 does nothing to increase the size of the allocation maps.

	David

-- 
David Laight: david@l8s.co.uk