Date: Mon, 3 May 2004 21:44:58 +0300 From: Ion-Mihai Tetcu <itetcu@apropo.ro> To: "Kevin A. Pieckiel" <pieckiel+freebsd-questions@sdf.lonestar.org> Cc: freebsd-questions@freebsd.org Subject: Re: What is bps/cpg? Message-ID: <20040503214458.7af4a022@it.buh.cameradicommercio.ro> In-Reply-To: <20040430180659.GA6873@SDF.LONESTAR.ORG> References: <20040430180659.GA6873@SDF.LONESTAR.ORG>
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On Fri, 30 Apr 2004 14:07:00 -0400 "Kevin A. Pieckiel" <pieckiel+freebsd-questions@sdf.lonestar.org> wrote: > I was reading the man page for bsdlabel, specifically looking for what the > bps/cpg value for a new filesystem should be. The man page states: > > bps/cpg > For 4.2BSD file systems, the number of cylinders in a cylinder > group. For LFS file systems, the segment shift value. Defaults > to 16 for partitions smaller than 1GB, 64 for partitions 1GB or > larger. > > Okay. Sure. That leaves a few questions: > > 1. What is the purpose of cylinder groups? > 2. What are "reasonable" values for this parameter? > 3. Why, if the default is 16 or 64, did sysinstall create my various > filesystems (on various machines) with values of 8, 28552, or 32776? > > I'm just trying to understand why this value is set to these numbers by > sysinstall, and to what I should set this value when I add a HDD to a > computer. Try reading the comments in /usr/src/sys/ufs/* beginning with /usr/src/sys/ufs/ffs/fs.h. Do it with a piece of paper and a pencil at hand ;-) -- IOnut Unregistered ;) FreeBSD "user"
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