From owner-freebsd-fs Sat Aug 28 16:40:27 1999 Delivered-To: freebsd-fs@freebsd.org Received: from mail.du.gtn.com (mail.du.gtn.com [194.77.9.57]) by hub.freebsd.org (Postfix) with ESMTP id 033B214D8C for ; Sat, 28 Aug 1999 16:40:24 -0700 (PDT) (envelope-from ticso@cicely8.cicely.de) Received: from mail.cicely.de (cicely.de [194.231.9.142]) by mail.du.gtn.com (8.9.3/8.9.3) with ESMTP id BAA04443; Sun, 29 Aug 1999 01:37:21 +0200 (MET DST) Received: from cicely8.cicely.de (cicely8.cicely.de [10.1.2.10]) by mail.cicely.de (8.9.0/8.9.0) with ESMTP id BAA01607; Sun, 29 Aug 1999 01:37:18 +0200 (CEST) Received: (from ticso@localhost) by cicely8.cicely.de (8.9.3/8.9.2) id BAA28142; Sun, 29 Aug 1999 01:36:57 +0200 (CEST) (envelope-from ticso) Date: Sun, 29 Aug 1999 01:36:56 +0200 From: Bernd Walter To: Terry Lambert Cc: Bernd Walter , freebsd-fs@FreeBSD.ORG Subject: Re: fs-locking and fs memory copies questions Message-ID: <19990829013655.E27811@cicely8.cicely.de> References: <19990828201723.A27704@cicely8.cicely.de> <199908282249.PAA06168@usr01.primenet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.3i In-Reply-To: <199908282249.PAA06168@usr01.primenet.com>; from Terry Lambert on Sat, Aug 28, 1999 at 10:49:51PM +0000 Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Sat, Aug 28, 1999 at 10:49:51PM +0000, Terry Lambert wrote: > This is the problem with growing FS's: the hash fill on the > preexisting cylinger groups will be higher than on the new > cylinder groups, leading to fragmentation. Mmmmm - I can't follow you on this. The existing cg's are prefilled with old files. The new ones are empty after growing. I beleaved ffs would prever the new ones automaticaly because of the super-blocks summary information. Guess I need to look more deeply at the block-searching routines. At least the problems created with that should loose during usage. > > A generic defragger would be a good think to have, if you wanted > to allow shrinking partitions, too. > I already need to move blocks around in case the superblock-summary information needs another frag. It was one of the more difficult things to do there are still some erros left about this - the rest was quite easy. Shrinking is something I don't beleave to get working properly, because that would mean loosing cg's with all their inodes. Moving files to different inodes is generaly a mess for NFS-servers. Another point is that finding the reference for a frag is a real expensive thing to do :( -- B.Walter COSMO-Project http://www.cosmo-project.de ticso@cicely.de Usergroup info@cosmo-project.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message