From owner-freebsd-fs@FreeBSD.ORG Mon Jun 27 13:40:21 2005 Return-Path: X-Original-To: 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 4A85116A41C for ; Mon, 27 Jun 2005 13:40:21 +0000 (GMT) (envelope-from delphij@frontfree.net) Received: from tarsier.geekcn.org (tarsier.geekcn.org [210.51.165.229]) by mx1.FreeBSD.org (Postfix) with ESMTP id C122743D62 for ; Mon, 27 Jun 2005 13:40:20 +0000 (GMT) (envelope-from delphij@frontfree.net) Received: from beastie.frontfree.net (unknown [219.239.99.7]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by tarsier.geekcn.org (Postfix) with ESMTP id CAF9FEB249F for ; Mon, 27 Jun 2005 21:40:17 +0800 (CST) Received: from localhost (localhost.frontfree.net [127.0.0.1]) by beastie.frontfree.net (Postfix) with ESMTP id 7BF7E1320CD; Mon, 27 Jun 2005 21:40:15 +0800 (CST) Received: from beastie.frontfree.net ([127.0.0.1]) by localhost (beastie.frontfree.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 05105-11; Mon, 27 Jun 2005 21:40:09 +0800 (CST) Received: by beastie.frontfree.net (Postfix, from userid 1001) id 80D3D13205E; Mon, 27 Jun 2005 21:40:08 +0800 (CST) Date: Mon, 27 Jun 2005 21:40:08 +0800 From: Xin LI To: Skylar Thompson Message-ID: <20050627134008.GA5764@frontfree.net> References: <20050626182031.GA5268@quark.cs.earlham.edu> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="k+w/mQv8wyuph6w0" Content-Disposition: inline In-Reply-To: <20050626182031.GA5268@quark.cs.earlham.edu> User-Agent: Mutt/1.4.2.1i X-GPG-key-ID/Fingerprint: 0xCAEEB8C0 / 43B8 B703 B8DD 0231 B333 DC28 39FB 93A0 CAEE B8C0 X-GPG-Public-Key: http://www.delphij.net/delphij.asc X-Operating-System: FreeBSD beastie.frontfree.net 5.4-RELEASE-p1 FreeBSD 5.4-RELEASE-p1 #1: Fri May 27 00:47:15 CST 2005 delphij@beastie.frontfree.net:/usr/obj/usr/src/sys/BEASTIE i386 X-URL: http://www.delphij.net X-By: delphij@beastie.frontfree.net X-Location: Beijing, China X-Virus-Scanned: amavisd-new at frontfree.net Cc: fs@freebsd.org Subject: Re: Snapshot 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: Mon, 27 Jun 2005 13:40:21 -0000 --k+w/mQv8wyuph6w0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jun 26, 2005 at 01:20:31PM -0500, Skylar Thompson wrote: > I've discovered a repeatable problem with FreeBSD's UFS2 snapshots. If I > create several snapshots, and then do heavy disk I/O on the original > filesystem (deletions, creations, simple touches, etc.) I can cause the I= /O > system to crash. There is no kernel panic, and the machine still answers > pings, but no disk I/O occurs. I can replicate this on a dual-processor > beige-box system with a Mylex RAID controller and a RAID-5 set, and also = on > a dual-processor Dell Poweredge 2650 with a PERC 3/i RAID controller and a > RAID-5 set and RAID-1 set. FreeBSD 5.4-RELEASE is installed on both > systems, and SMP is enabled as well, with HTT disabled on the Poweredge. I > have DDB compiled in, so I can get debug information but I don't know what > to look for. I think a script that can reliably trigger the "crash" would be helpful. What do you mean by "IO system crash", BTW? I got confused since it does not cause kernel panic and stop ping responses. Do you mean that the I/O system was stalled/suspended when there is heavy disk operations? My guess is that there is some underlying deadlock(s) present. Would you mind compiling WITESS/WITESS_SUPPORT into your kernel and give it a try? This will reduce performance, but would also be helpful for picking locking bugs. Thanks in advance! Cheers, --=20 Xin LI http://www.delphij.net/ See complete headers for GPG key and other information. --k+w/mQv8wyuph6w0 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQFCwAG4/cVsHxFZiIoRAsDvAKCIIHcGqSx3btWHVgfqE2s9HmMNFACfYRdh TTmCWZEvoMVYBK1buCScNDY= =Iqkn -----END PGP SIGNATURE----- --k+w/mQv8wyuph6w0--