From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars Marowsky-Bree Subject: Re: Summary of the Multi-Path BOF at OLS and future directions Date: Thu, 7 Aug 2003 09:38:14 +0200 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030807073814.GB12862@marowsky-bree.de> References: <1060042082.1985.53.camel@fuzzy> <20030805171416.A7963@beaverton.ibm.com> <1060201601.25773.30.camel@persist.az.mvista.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3lcZGd9BuhuYXNfi" Return-path: Content-Disposition: inline In-Reply-To: <1060201601.25773.30.camel@persist.az.mvista.com> To: Steven Dake , Patrick Mansfield Cc: James Bottomley , SCSI Mailing List , linux-raid@vger.kernel.org List-Id: linux-raid.ids --3lcZGd9BuhuYXNfi Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2003-08-06T13:26:41, Steven Dake said: > There are problems with multipath in the md driver, specifically how to > manage partitions. Each partition requires a seperate multipath.=20 This is indeed a deficiency, but it all depends on how the DM device is setup. You can also setup the DM for the physical device and then the partitions on top of the DM, either using the partition code in the kernel or, better, using user-space discovery and creating appropriate DM devices to match the partitions. > Changing partition sizes is quite difficult after multipaths are setup.= =20 > One could argue that partitions should be managed by device mapper, but > unfortunately all firmware doesn't know about device mapper devices, > requiring the use of partitions. Whether DM manages partitions or not is unrelated to whether firmware knows about them; firmware depends on how the metadata is represented on disk, not how (and where, whether 'in kernel' or DM) Linux choses to interpret it. > Also most people don't want to mess with device mapper. Tough ;-) > I like the idea of a generic queueing interface for block commands > integrated with multipathing as it solves the partitioning problem quite > nicely. This would of course also be nice. Sorry for getting into the discussion so late on the list here. I really managed to miss it. I wonder how ever I did that... Sincerely, Lars Marowsky-Br=E9e --=20 SuSE Labs - Research & Development, SuSE Linux AG =20 "If anything can go wrong, it will." "Chance favors the prepared (mind)." -- Capt. Edward A. Murphy -- Louis Pasteur --3lcZGd9BuhuYXNfi Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.7 (GNU/Linux) iD8DBQE/MgHmudf3XQV4S2cRAtI5AJ4vtm/KCpzuDWhi85SAm8l3Q76nxgCfWKew v/LiAJbFvuCwkd/I8BuhyyU= =+6mO -----END PGP SIGNATURE----- --3lcZGd9BuhuYXNfi--