Path: utzoo!attcan!uunet!samsung!uakari.primate.wisc.edu!sdd.hp.com!hplabs!hpfcso!hpfcmgw!rocky
From: rocky@hpfcmgw.HP.COM (Rocky Craig)
Newsgroups: comp.sys.hp
Subject: Re: minfree, inodes
Message-ID: <17780008@hpfcmgw.HP.COM>
Date: 11 Feb 91 20:48:54 GMT
References: <1991Feb08.161751.13172@eye.com>
Organization: HP Fort Collins, CO
Lines: 34

> I've been setting up filesystem with "newfs -i 8192 -m 5"....Am I crazy?

Well, check rec.shrink for a second opinion:-)  My group stages tradeshows 
for HP, so we create lots of new filesystems on a regular basis.
We have "evolved" into using the values you quoted for a variety of
technical and empirical reasons.

1. Using the default values for inodes (1024 bytes/inode) does waste a lot
   of space.  Execute "bdf -i" on a "mature" file system using that bytes/node
   value and compare inode % free vs. file system % free.  8192 has been 
   a safe choice.  16384 starts getting into the realm of discomfort, and
   doesn't buy you that much more over 8192.
2. We use "-m 5".  Why 5?  Because it works and hasn't bitten us yet :-)
   Back in the days of 50M disks, 10% was not very much space.  Today's
   500M (and more) disks can waste a lot more space.  The minfree is supposed
   to be for root recovery space AND performance, but when we use
   "-m 5" we see no NOTICEABLE performance degradation.  And in a trade show,
   you know somebody is watching your performance CLOSELY.  We'd rather have 
   the space for one or two extra demos sets.

   If you're only concerned about having enough space for root to clean up
   things (i.e., leave 5 meg regardless), scale your fudge space against 
   your disk capacity.

BTW, this discussion made the rounds internally at HP a few months back.
It looked remarkably like your standard "vi" vs. "emacs" wars :-)  The
bottom line: if it works, use it.

Rocky Craig			
rocky%hpfcmr@hplabs.hp.com

This article does not represent the official position of the Hewlett-Packard 
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