Summary: Disk performance and space tuning

From: Jiri Dvorak (
Date: Mon Feb 18 1991 - 04:47:30 CST

Last week I asked how to set the tuning parameters with newfs and tunefs
for different filesystems, in particular /export/swap, to achieve both
high performance and maximum space.
I got just 1 answer, which is included below in full length.

Many thanks to Bill Vaughn

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>From Wed Feb 13 19:03:10 1991
Subject: Re: Disk performance and space tuning

I have my /export/swap mounted on a separate file system and therfore
have a script create the swap files. The key commands in this script

newfs -v -m 0 -i 10000000 -c 32 /dev/rxd1d
tunefs -e 4000 /dev/rxd1d

The m option allows me to use all the space. After all I don't
anticipate any more files being created there.
The i option gives me the minimum number of inodes ( I only need 15 or so).
The c option gives me 32 cylinder per group instead of the default 16. This
should use less space overhead and helps keep the file blocks together.

The e option in tuenfs sets the max-contig' value very high so as to keep
the blocks of any swap file fairly close together on the disk. Together
with the c option of the newfs command this should get the maximum
localization possible with the filesystem parameters.

I've never run any comparison tests on this setup with the 'default'
setup one would get. It just seems like the thing to do.

Let me know if I'm wrong.

Bill Vaughn

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