From owner-freebsd-hackers Wed May 20 10:18:13 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA05580 for freebsd-hackers-outgoing; Wed, 20 May 1998 10:18:13 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from hub.org (hub.org [209.47.148.200]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA05475 for ; Wed, 20 May 1998 10:17:59 -0700 (PDT) (envelope-from scrappy@hub.org) Received: from localhost (scrappy@localhost) by hub.org (8.8.8/8.7.5) with SMTP id NAA01073; Wed, 20 May 1998 13:17:35 -0400 (EDT) Date: Wed, 20 May 1998 13:17:34 -0400 (EDT) From: The Hermit Hacker To: Tom cc: Bruce Momjian , mimo@interdata.com.pl, hackers@FreeBSD.ORG, hackers@postgreSQL.org Subject: Re: [HACKERS] sorting big tables :( In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, 20 May 1998, Tom wrote: > > On Wed, 20 May 1998, The Hermit Hacker wrote: > > > One of the things that the Unix FS does is auto-defragmenting, at > > least the UFS one does. Whenever the system is idle (from my > > understanding), the kernel uses that time to clean up the file systems, to > > reduce the file system fragmentation. > > No, that doesn't happen. The only way to eliminate fragmentation is a > dump/newfs/restore cycle. UFS does do fragmentation avoidance (which is > reason UFS filesystems have a 10% reserve). Okay, then we have two different understandings of this. My understanding was that the 10% reserve gave the OS a 'temp area' in which to move blocks to/from so that it could defrag on the fly... Am CC'ng this into freebsd-hackers@freebsd.org for a "third opinion"...am willing to admit I'm wrong *grin* To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message