From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andre Noll Subject: Re: Poor write performance with write-intent bitmap? Date: Wed, 22 Apr 2009 16:21:48 +0200 Message-ID: <20090422142148.GC13280@skl-net.de> References: <49ED096E.1000002@anonymous.org.uk> <49ED16F7.3040906@anonymous.org.uk> <4081b80da35818efbc07723240f8ea36.squirrel@neil.brown.name> <49ED2BC3.7050109@anonymous.org.uk> <87d4b5m4kf.fsf@frosties.localdomain> <49EF108D.4070605@anonymous.org.uk> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="8NvZYKFJsRX2Djef" Return-path: Content-Disposition: inline In-Reply-To: <49EF108D.4070605@anonymous.org.uk> Sender: linux-raid-owner@vger.kernel.org To: John Robinson Cc: Goswin von Brederlow , Linux RAID List-Id: linux-raid.ids --8NvZYKFJsRX2Djef Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 13:41, John Robinson wrote: > >Normal shutdown should put the raid in read-only mode as last step. At > >least Debian does that. That way even a mounted raid will be clean > >after reboot. >=20 > Yes, I would have thought it should as well. But I've just looked at=20 > CentOS 5's /etc/rc.d/halt and as far as I can see it doesn't try to=20 > switch md devices to read-only. There's no need to do that in the shutdown script as the kernel will switch all arrays to read-only mode on halt/reboot. Moreover, as raid arrays are automatically marked clean if no writes are pending for some small time period, a simple "sync; sleep 1" at the end of the shutdown script is usually enough to have a clean array during the next boot. An alternative way to deal with this issue is to not have a root file system at all but to mount/link each top level directory separately. This allows to stop all md arrays cleany. Andre --=20 The only person who always got his work done by Friday was Robinson Crusoe --8NvZYKFJsRX2Djef Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFJ7yf8Wto1QDEAkw8RAg7kAJ9JlttrKZJqKHk7GAP1Y6DnENgH1QCgoNKu to6czP04gT0cpV8f0XTntLg= =aTo/ -----END PGP SIGNATURE----- --8NvZYKFJsRX2Djef--