From owner-freebsd-questions Thu Apr 29 9: 9:46 1999 Delivered-To: freebsd-questions@freebsd.org Received: from mail.HiWAAY.net (fly.HiWAAY.net [208.147.154.56]) by hub.freebsd.org (Postfix) with ESMTP id D43DF14E5F for ; Thu, 29 Apr 1999 09:09:44 -0700 (PDT) (envelope-from dkelly@nospam.hiwaay.net) Received: from nospam.hiwaay.net (tnt8-216-180-14-89.dialup.HiWAAY.net [216.180.14.89]) by mail.HiWAAY.net (8.9.1a/8.9.0) with ESMTP id LAA00913 for ; Thu, 29 Apr 1999 11:09:42 -0500 (CDT) Received: from nospam.hiwaay.net (nospam.hiwaay.net [127.0.0.1]) by nospam.hiwaay.net (8.9.2/8.9.2) with ESMTP id KAA53587 for ; Thu, 29 Apr 1999 10:37:30 -0500 (CDT) (envelope-from dkelly@nospam.hiwaay.net) Message-Id: <199904291537.KAA53587@nospam.hiwaay.net> X-Mailer: exmh version 2.0.2 2/24/98 To: freebsd-questions@freebsd.org From: David Kelly Subject: Re: BSD Software RAID 0 and 1? Journaling file system? In-reply-to: Message from Alfred Perlstein of "Wed, 28 Apr 1999 22:38:03 CDT." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 29 Apr 1999 10:37:30 -0500 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Alfred Perlstein writes: > On Thu, 29 Apr 1999, Greg Lehey wrote: > > You may have misunderstood the question. When a journaling/logging > > file system crashes, you don't need to run fsck: you replay the log. > > It makes up for the faster fsck by slower performance all the time. > > This is probably why nobody has been too concerned about it in the > > past. > > Er.... when you have a logging filesystem you can have an in place > log, since the superblock points to the last sucessful checkpoint > you just need to examine all partial segements after the last > sucessful checkpoint verifying thier completeness. > > I don't think you have to sacrifice speed at all as segments > written out can contain both metadata and data blocks, in fact > 4.4 BSD's LFS is superior at writing isn't it? I haven't measured it but having spent much of the last couple of years using Irix systems with XFS filesystems and FreeBSD, I believe both systems can do file I/O at about the same rate on identical HD's but XFS is much faster at metadata than even softupdates. Systems are an SGI O2 R5000 180 MHz with 64MB, FreeBSD 3.0 on a P-II 233 MHz with 64MB. Disks are identical Seagate 9G, ST19173W (if memory serves). A good example benchmark would be to extract the FreeBSD ports directory. Thousands of little files and directories. Another example would be "du -sk" on a directory with about 40,000 files. -- David Kelly N4HHE, dkelly@nospam.hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message