Subject: Re: errors in "New features list"
To:, SODA Noriyuki <>
From: Pavel Cahyna <>
List: netbsd-docs
Date: 10/14/2004 13:04:48

> > FFSv1 already supports filesystems larger than 1TB, so the entry about
> > UFS2 in the INSTALL document and the Guide is also incorrect. I propose
> > changing it to "UFS2 is better suited for file systems larger than 1
> > Terabyte".
> Erm, to my knowledge the only (relevant) differences are:
> - FFSv2 inodes are twice the size of FFSv1 inodes, so the space used
>   for file system red tape is about twice the size.
> - FFSv2 newfs doesn't have to write all the inode blocks so is quicker.
> FFSv2 does allow > 2^31 fragments in a filesystem, but since NetBSD has
> a limit of 2^32 sectors on a disk (due to the label) this is not relevant.

This means that for > 1TB filesystems, one must use 1KB fragment size
with FFSv1, where one would use 512 bytes with FFSv2. With a lot of files,
this would mean a lot more wasted space with FFSv1. That's what I meant by
"better suited for filesystems larger than 1TB." (Also, I do not have any
such filesystem, tho this is just my theories.)

> The FFSv2 import did change the way newfs creates FFSv1 filesystems, and
> thus removed some of the file system size restrictions that were previously
> present.

That is interesting, what restrictions were previously present?

Bye	Pavel