16384/2048.
Following recent discussions on the -arch mailing list, involving dillon
and mckusick, this change parallels the one made over a decade ago when
the default was bumped up from 4096/512.
This should provide significant performance improvements for most
folks, less significant performance losses for a few folks and
wasted space lost to large fragments for many folks.
For discussion, please see the following thread in the -arch archive:
Subject: Using a larger block size on large filesystems
The discussion ceases to be relevant when the issue of partitioning
schemes is raised.
were only of benefit to large filesystems, which recent research
suggests is not the case, and which the original author of the text
no longer endorses.
size ratio other than 8:1. Currently, we only recommend an 8:1
ratio, because the impact of others ratios has not been adequately
investigated.
Also, do not recommend the use of the -c option in the example, since
newfs now automatically calculates the best cyl:cylgrp ratio.
This change was discussed with the author of rev 1.29.
[I first added this functionality, and thought to check prior art. Seeing
OpenBSD had already done this, I changed my addition to reduce the diffs
between the two and went with their option letter.]
Obtained from: OpenBSD
Add -v flag to newfs:
-v Specify that the partition does not contain any slices, and that
newfs should treat the whole partition as the file system. This
option is useful for synthetic disks such as ccd and vinum.
We pretend we have one head with two megabyte worth of sectors per cylinder.
The code try to access another head in what it belives to the same
physical cylinder, because it belives that it would be faster than
waiting for the next free sector under this head to come around.
Most modern drives doesn't have a "classical" geometry, and thus
we end up fooling ourselves doing the above optimization. With this
change we will fill a cylinder sequentially if we can, and thus get
much more mileage from the track-buffer/cache built into the drives.
As a result a lot of seeks to the next or previous track should be
avoided by this.
(My disk is a lot less noisy actually...)
You can still get the old behaviour, by specifying zero for the
numbers.
This will also solve the problem with newfs barfing at really big
drives.
Obtained from: adult advice from Kirk.
being output if <= 1 rpos; there is a bug in the kernel which doesn't
quite get along with this. Changed default #rpos to 1, and fixed up
manual page. Converted nrpos to 1 if user specifies 0.
