From owner-freebsd-fs@FreeBSD.ORG Tue Mar 21 20:07:12 2006 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2B8CB16A400; Tue, 21 Mar 2006 20:07:12 +0000 (UTC) (envelope-from john@kozubik.com) Received: from kozubik.com (kozubik.com [69.43.165.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id D67D143D48; Tue, 21 Mar 2006 20:07:11 +0000 (GMT) (envelope-from john@kozubik.com) Received: from kozubik.com (localhost [127.0.0.1]) by kozubik.com (8.12.11/8.12.11) with ESMTP id k2LK74Om034435; Tue, 21 Mar 2006 12:07:04 -0800 (PST) (envelope-from john@kozubik.com) Received: from localhost (john@localhost) by kozubik.com (8.12.11/8.12.11/Submit) with ESMTP id k2LK74uq034432; Tue, 21 Mar 2006 12:07:04 -0800 (PST) (envelope-from john@kozubik.com) Date: Tue, 21 Mar 2006 12:07:04 -0800 (PST) From: John Kozubik To: Kris Kennaway In-Reply-To: <20060321194904.GA20959@xor.obsecurity.org> Message-ID: <20060321120255.I55763@kozubik.com> References: <20060320224313.O55763@kozubik.com> <20060321184127.GA19204@xor.obsecurity.org> <20060321113923.I55763@kozubik.com> <20060321194904.GA20959@xor.obsecurity.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: freebsd-fs@freebsd.org, jroberson@chesapeake.net, tegge@freebsd.org Subject: Re: UFS2 Snapshots in 6.1-Beta4 - Confirmed Problems X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Mar 2006 20:07:12 -0000 On Tue, 21 Mar 2006, Kris Kennaway wrote: > > > > This next one is complicated, and I haven't submitted a PR for it yet, but > > > > I believe it is quite serious for reasons I will expand on below. > > > > > > > > The problem is: If you completely fill a filesystem (109% usage in `df` > > > > on most systems) that has a snapshot on it, the system becomes very > > > > unresponsive - all interactive and disk response lags terribly and, > > > > although the system is not hung, it is in many cases unusable. > > > > > > Yes :-( This will probably not be fixable in time for 6.1, but > > > hopefully it will be addressed in the future. FYI, the system may > > > also panic in this situation. > > > > > > Because my original description of this behavior was so vague, I was going > > to try to reproduce it again with more details, however it sounds like you > > have already witnessed this and know more about it than I do. > > > > Is that true ? Can I skip a few hours of trying to reproduce this ? > > Yes, I'm easily able to reproduce it, and I'm told that fixing it will > require fairly extensive work & testing. Ok. Please contact me when that testing is needed as I am happy to help. Can I use this time to suggest that in all testing of snapshot related issues, that multiple (preferably 4+) snapshots per filesystem are used ? Many of the problems either do not manifest themselves, or are not as pronounced with only one snapshot running. Thanks. ----- John Kozubik - john@kozubik.com - http://www.kozubik.com