Subject: Re: errors in "New features list"
To: Pavel Cahyna <>
From: David Laight <>
List: netbsd-docs
Date: 10/13/2004 20:27:00
> 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.

Both versions have a limit of 2^31 (maybe 32) inodes, and restrict the
cylinder group size by requiring the allocation bitmaps fit in a single
file system block (this is what makes lareg fs have 1000s of cylinder

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


David Laight: