On Tue, 6 Aug 2002, Christian Hattemer wrote:

> to take all advantages from the new FFS layout algorithm, is it recommended
> to start with a fresh installation to have the whole disk in this new layout?
>
> When updating, parts of the disk would still be in the old layout and limit
> the speedup.

	Correct. There are three obvious layout changes from 1.5.2:
	a) The new dirpref - this changes the way directories are spread
	   across cylinder groups and can make a significant improvement
	   to large directory trees (such as pkgsrc :)
	   You can gain most of the benefit by recreating directory
	   trees.

	b) Default block and fragment size.
	   In 1.5.2 and earlier the default FFS blocksize is 8K, and
	   fragments 16K. In 1.6 (and possibly 1.5.3) larger filesystems
	   will get 16K/2K, and very small filesystems 4K/0.5K. For large
	   filesystems this reduces the amount of metadata and increases
	   the average transfer size. The first is a win for fsck time, the
	   latter a win pretty much everywhere. It does mean more wasted
	   space for small files, but I've found this is generally won back
	   by the reduced metadata. Needs newfs.

	c) Cylinders per group increased from 16 to the maximum permitted by
	   the disk geometry and blocksize. A smaller win, but makes better
	   use of the metadata and tends to reduce cylinder groups on big
	   disks from thousands to a hundred or so. Again, needs newfs.

	This is in addition to the obvious softdep and other improvements,
	and in 1.6 UBC and other wins :)

> BTW: The install notes say about updating:
> "Finally, you will want to delete old binaries that were part of the version
>  of NetBSD that you upgraded from and have since been removed from the NetBSD
>  distribution."
>
> How do I find out which files to delete?

	sysinst should have an obsolete list. Alternatively run a 'tar tf'
	for each of the install tarsets and compare with you installed
	files :)

-- 
		David/absolute		-- www.netbsd.org: No hype required --