Date: Sat, 3 Apr 1999 12:50:01 -0800 (PST) From: Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/10927: Bug in UFS/FFS: time / space optimization on large partitions Message-ID: <199904032050.MAA00565@freefall.freebsd.org>
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The following reply was made to PR kern/10927; it has been noted by GNATS.
From: Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de>
To: bde@zeta.org.au (Bruce Evans)
Cc: FreeBSD-gnats-submit@FreeBSD.ORG,
oliver.fromme@heim3.tu-clausthal.de
Subject: Re: kern/10927: Bug in UFS/FFS: time / space optimization on large partitions
Date: Sat, 3 Apr 1999 18:33:00 +0200 (MET DST)
Bruce Evans wrote:
> The switch from TIME to SPACE occurs when there are too many fragments.
Oh. I didn't know that. I thought it was a function of free
space on the partition.
> For a filesystem with the default block size of 8K, the default fragment
> size of 1K, the default minfree of 8%, and the unlikely fragmentation
> amount of 100%, it occurs when the filesystem is 1/48 (about 2%) full.
> For a 40% full disk it only takes 5% fragmentation to invoke the switch.
That explains it, indeed:
212516 files, 3253264 used, 5434872 free
(451720 frags, 622894 blocks, 5.2% fragmentation)
So the PR can be closed, of course. Sorry for the confusion.
I was probably confused by the description in newfs(8), but the
description in tunefs(8) is more clear.
By the way, what would be better filesystem parameters, in
order to have optimization for time, as long as possible?
Regards
Oliver
--
Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany
(Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de)
"In jedem Stück Kohle wartet ein Diamant auf seine Geburt"
(Terry Pratchett)
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