From owner-freebsd-stable Tue Jul 23 15:47:51 2002 Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 56AE337B400 for ; Tue, 23 Jul 2002 15:47:49 -0700 (PDT) Received: from mail3.dreamscape.com (mail3.dreamscape.com [206.64.128.213]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8503943E6E for ; Tue, 23 Jul 2002 15:47:48 -0700 (PDT) (envelope-from krentel@dreamscape.com) Received: from dreamscape.com (sA14-p27.dreamscape.com [209.217.195.27]) by mail3.dreamscape.com (8.9.3+blt/8.9.3) with ESMTP id SAA14520; Tue, 23 Jul 2002 18:47:41 -0400 (EDT) Received: from blue.mwk.domain (localhost [127.0.0.1]) by dreamscape.com (8.11.1/8.11.1) with ESMTP id g6NMl3533962; Tue, 23 Jul 2002 18:47:04 -0400 (EDT) (envelope-from krentel@blue.mwk.domain) Message-Id: <200207232247.g6NMl3533962@dreamscape.com> To: dillon@apollo.backplane.com Cc: freebsd-stable@FreeBSD.ORG Subject: Re: 4.6-RC: Glacial speed of dump backups Date: Tue, 23 Jul 2002 18:47:03 -0400 From: "Mark W. Krentel" Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Matthew Dillon wrote: > Dump has always had problems dealilng with live filesystems, and its > even worse now that we can't dump via a buffered block device because > the filesystem state is going to be out of sync from the raw device > whether dump re-reads the inodes or not. So even though dump does try > to re-read inodes to check for changes, it is unlikely that our meager > cache will make things worse then the kernel's buffer cache already > makes them. I asked about this on -hackers last week. In Linux, the 2.4 kernels make it impossible for ext2 dump to always see the correct versions of some files, even if there are no writes during the dump. http://old.lwn.net/2001/0503/a/lt-dump.php3 http://old.lwn.net/2001/0503/a/lt-metadata.php3 Are you saying Freebsd has the same problem? I know that dump will have problems when the file system is changing during the dump, but the Linux problems go far beyond that. I did some simple tests and everything works as I'd expect in Freebsd, although it's easy to make Linux fall over. --Mark To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message