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Received: by minnie.vk1xwt.ampr.org with NNTP id AA6229 ; Wed, 06 Jan 93 04:13:13 EST Xref: sserve comp.unix.ultrix:15875 comp.unix.misc:6172 comp.unix.bsd:9721 comp.arch.storage:812 Path: sserve!manuel.anu.edu.au!munnari.oz.au!uunet!news.mtholyoke.edu!jbotz From: jbotz@mtholyoke.edu (Jurgen Botz) Newsgroups: comp.unix.ultrix,comp.unix.misc,comp.unix.bsd,comp.arch.storage Subject: Filsystem performance and cylinder(group) alignment Date: 8 Jan 1993 11:51:08 -0500 Organization: Mount Holyoke College Lines: 29 Sender: news@mtholyoke.edu Distribution: world Message-ID: <1ikbdsINN1nv@slab.mtholyoke.edu> References: <1ihufqINNp1p@slab.mtholyoke.edu> NNTP-Posting-Host: slab.mtholyoke.edu In article <1ihufqINNp1p@slab.mtholyoke.edu> I asked: >I am somewhat mystified by the process of changing disk partitions >under Ultrix (4.x). In "The Unix System Administration Handbook" >(Evi & Nemeth) it states that BSD systems must have partition >boundaries aligned with cylinders (or even cylinder groups?) or >take a serious performance penalty. Is this also true for Ultrix >(which is derived from 4.2BSD) or does the Ultrix automatically >align partitions on cylinder boundaries? [...] I received a number of responses to this question, some of which were a bit conflicting. Some people say that yes, aligning partitions with cylinder group boundaries is important, others say that with modern disks it doesn't matter very much. One thing is clear: many of the default parititions in Ultrix's /etc/disktab do /not/ align with cylinder boundaries. So I'm asking again, with the newsgroup list expanded to comp.unix.bsd and comp.arch.storage because a lot of people asked me to forward responses to them, so I gather this is a topic of considerable confusion... on a relatively modern 1GB disk (such as an rz57), am I or am I not going to take a considerable performance hit if my (BSD fast-)filesystems are not aligned with cylinder (and cylinder-group) boundaries? I will post a summary in a few days. -- Jurgen Botz, jbotz@mtholyoke.edu Northampton, MA, USA