From owner-freebsd-current@FreeBSD.ORG Thu Jul 26 13:43:30 2007 Return-Path: Delivered-To: current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C4D9016A421 for ; Thu, 26 Jul 2007 13:43:30 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: from mail.garage.freebsd.pl (arm132.internetdsl.tpnet.pl [83.17.198.132]) by mx1.freebsd.org (Postfix) with ESMTP id 2BA3513C4CB for ; Thu, 26 Jul 2007 13:43:27 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: by mail.garage.freebsd.pl (Postfix, from userid 65534) id D195D456AB; Thu, 26 Jul 2007 15:43:23 +0200 (CEST) Received: from localhost (154.81.datacomsa.pl [195.34.81.154]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.garage.freebsd.pl (Postfix) with ESMTP id D2D5845696; Thu, 26 Jul 2007 15:43:13 +0200 (CEST) Date: Thu, 26 Jul 2007 15:42:31 +0200 From: Pawel Jakub Dawidek To: Craig Boston , Dmitry Morozovsky , current@FreeBSD.org Message-ID: <20070726134231.GO12473@garage.freebsd.pl> References: <20070725234322.G33266@woozle.rinet.ru> <20070725222035.GA50522@nowhere> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="FxlYARId5dseejUu" Content-Disposition: inline In-Reply-To: <20070725222035.GA50522@nowhere> User-Agent: Mutt/1.4.2.3i X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 7.0-CURRENT i386 X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on mail.garage.freebsd.pl X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=BAYES_00 autolearn=ham version=3.0.4 Cc: Subject: Re: ZFS on a notebook/512M settings X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Jul 2007 13:43:30 -0000 --FxlYARId5dseejUu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 25, 2007 at 05:20:35PM -0500, Craig Boston wrote: > I've seen recommendations on the BSD lists to use zil_disable to avoid > low-memory deadlocks (which I've not yet encountered). I've also seen > dire warnings on the OpenSolaris lists about possible data corruption if > you disable the ZIL, so I'm unsure about that one. For now I'm erring > on the side of caution and leaving it enabled until it causes me > problems. Let me explain what disabling ZIL really means. Once ZIL is disabled, fsync(2) is a no-op, ie. calling fsync(2) on a descriptor doesn't mean your data would be safely stored on disk at the time function returns. There is no data corruption for local use, only this fsync(2) problem. "Data corruption" can happen from NFS client point of view, when your ZFS file system is exported over NFS and your NFS server crashes. You can read more details here: http://blogs.sun.com/roch/entry/nfs_and_zfs_a_fine --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --FxlYARId5dseejUu Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFGqKTHForvXbEpPzQRApp4AJ9SpyiQrxBuB31crhB87BMV/XaVIQCfRz+p sgn2MdNnCU4gn+UGZJx+I5Q= =OMNg -----END PGP SIGNATURE----- --FxlYARId5dseejUu--