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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mira.net.au!Germany.EU.net!howland.reston.ans.net!swrinde!newsfeed.internetmci.com!uunet!not-for-mail From: davidsen@tmr.com (bill davidsen) Newsgroups: comp.unix.bsd.freebsd.misc,news.admin.technical,news.software.nntp Subject: Re: Poor performance with INN and FreeBSD. Date: 27 Mar 1996 00:02:54 -0500 Organization: TMR Associates, Schenectady NY Lines: 40 Sender: zorch@ftp.UU.NET Approved: zorch@uunet.UU.NET Distribution: world Message-ID: <4j9rce$210g@usenetw1.news.prodigy.com> References: <311F8C62.4BC4@pluto.njcc.com> <DoJ1Js.H2t@unixhub.SLAC.Stanford.EDU> <4ipb5c$24om@usenetw1.news.prodigy.com> <4j6l4a$9ia@web.nmti.com> NNTP-Posting-Host: ftp.uu.net Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:16031 news.admin.technical:1364 news.software.nntp:21040 In article <4j6l4a$9ia@web.nmti.com>, Peter da Silva <peter@nmti.com> wrote: | In article <4ipb5c$24om@usenetw1.news.prodigy.com>, | bill davidsen <davidsen@tmr.com> wrote: | > Having run on a log filesystem (JFS on AIX), I can tell you that the | > log file is the bottleneck. To get performance up, first I put the | > logfile on a dedicated disk (cut expire time by 3), and then on a | > dedicated solid state disk (cut expire time by 3 again). | | This paragraph doesn't make sense to me. Maybe I'm missing something, | but isn't the distinguishing feature of a log file system that all data | is *only* stored in the log? I'm not familiar with JFS, but the acronym | sounds like "Journalling File System"... which is to say a conventional | file system with a small log containing recent updates only and primarily | used for crash recovery rather than performance. Changes to the directory structure are written to the log logical volume (type jfslog), which is a circular queue. It's a separate logical volume, and can be on any device. Once a directory change has been written to the actual directory file the trailing pointer of the queue is moved. With an operation which has major file creation or deletion this becomes a bottleneck. | | The Sprite logging file system, the BDS LFS, and other pure logging | file systems don't have a separate "log file" that can be stored in | a dedicated disk or a solid-state disk. AIX JFS does. Every volume group has a logical volume of type jfslog which is used to do logging. It can be on any device in the volume group. And for the AIX challenged, a volume group is a group of physical devices, while a logical volume is sort of like a DOS partition, but which has characteristics like striped or not, mirrored or not, etc. By putting these jfslogs on a fast device the performance is significantly enhanced. -- -bill davidsen (davidsen@tmr.com) "As a software development model, Anarchy does not scale well." -Dave Welch