Subject: Re: File Size Limitations
To: Perry E. Metzger <perry@piermont.com>
From: David Laight <david@l8s.co.uk>
List: netbsd-docs
Date: 01/19/2005 00:09:45
On Mon, Jan 17, 2005 at 10:08:21PM -0500, Perry E. Metzger wrote:
> 
> "Geert Hendrickx" <geert.hendrickx@ua.ac.be> writes:
> > I also find there is very limited documentation on the filesystems
> > included in NetBSD.  About UFSv2 the docs only mention that "among other
> > enhancements, it is better suited for filesystems larger than 1 TB".
> > What does that mean, better suited?
> 
> It uses 64 bit block numbers instead of 32 bit ones. Since blocks are
> 512 bits, well, you can see why 2TB becomes a hard limit.

Nope, FFSv2 uses 64 bit fragment numbers, since fragments can be 64kB
FFSv1 can support filesystems with 2^31 x 64kB which is rather larger
than 2TB.

Under NetBSD the only differences are:
1) FFSv2 inodes are twice the size
2) FFSv2 netfs is faster - doesn't write all the inode sectors.
3) FFSv2 can be used with 512byte fragemnts on a 2^32 sector partition

	David

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