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From: torek@horse.ee.lbl.gov (Chris Torek)
Newsgroups: comp.unix.admin,comp.unix.bsd,comp.unix.internals,comp.unix.wizards
Subject: Re: why is altering MINFREE discouraged ?
Date: 20 Oct 1993 15:20:36 GMT
Organization: Lawrence Berkeley Laboratory, Berkeley CA
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Message-ID: <34862@dog.ee.lbl.gov>
References: <CF5DG9.6F@festival.ed.ac.uk> <PCG.93Oct19194620@decb.aber.ac.uk> <1993Oct20.143941.7910@cs.cornell.edu>
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In article <1993Oct20.143941.7910@cs.cornell.edu> chrisb@cs.cornell.edu
(Chris Buckley) writes:
>As always, I suspect it's very application dependent. ... previous times
>that this subject has come up nobody has reported problems using 3-5% on
>modern disks.

Indeed.  The 4.4BSD newfs now defaults to 5% as well.

Gordon Irlam's posting also reminds us that much space is wasted as
excess inodes, on most file systems.

Two `rules of thumb' I used, back when I made file systems for users :-) ,
were:

	-i 4096 for FSes with lots of small files (netnews? I forget
		what I used for news file systems)
	-i 6144 for `average' FSes
	-i 8192 for FSes with lots of large files

Rebuilding a file system---this is easiest when moving it from one
disk to another, or restoring one after a disk failure---with well-
tuned parameters (5% minfree, -i 6144) can give you tens of MB back,
or even hundreds on really big (> 2GB) partitions.  (10% of 2GB is
200 MB, so 5% is 100 MB right there.)
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 510 486 5427)
Berkeley, CA		Domain:	torek@ee.lbl.gov