From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k6HDaWIN022936 for ; Mon, 17 Jul 2006 09:36:32 -0400 Received: from bob.fastenal.com (bob.fastenal.com [205.243.112.24]) by mx3.redhat.com (8.13.1/8.13.1) with ESMTP id k6HDaOHI014602 for ; Mon, 17 Jul 2006 09:36:24 -0400 Message-ID: <44BB924F.7010301@fastenal.com> Date: Mon, 17 Jul 2006 08:36:15 -0500 From: Kelly Sauke MIME-Version: 1.0 Subject: Re: AW: [linux-lvm] SAN setup with host mirrored disks References: <7CA7BBF7F95AA245ACAB8E28A6285EB905191DA7@s01edv50.warema.de> In-Reply-To: <7CA7BBF7F95AA245ACAB8E28A6285EB905191DA7@s01edv50.warema.de> Content-Transfer-Encoding: quoted-printable Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="iso-8859-1"; format="flowed" To: LVM general discussion and development Fiederling, Daniel wrote: > Hi, > > thank you all for your answers. I currently test a setup with md for fail= over. > To clarify: we have two Clariions in two different locations that are use= d for failover. Of course on each Clariion the disks are set up as raid 5. = My question was about setting up a mirror that "copies" the data on each Cl= ariion. > =20 We use either Veritas Volume Manager or EMC MirrorView to accomplish=20 this. We've had no luck in our lab getting mirrored LVM volumes to work=20 properly. > Currently I use OpenSuSE 10.1 as distribution so unfortunately I can't us= e PowerPath because I only get rpms for sles or rhel that can't be installe= d. I know it's the wrong place for this question but: had someone success o= n installing PowerPath on non supported systems? > =20 There used to be a tarball install for PowerPath. I haven't used it for=20 about 3 years now since all we have are RHEL systems and the RPMs work=20 fine but they might still be shipping the tarball. > Kelly, I installed a package called multipath-tools version 0.4.6 which c= ontains multipath and multipathd by Christophe Varoqui. Is that the mpio pa= ckage you mentioned?=20 Yes, that is the package that I was talking about. > Why do I have to expect io errors when using md? What is special about th= e Clariion setup? I would expect that the san disks are only "normal" scsi = disks for linux... > =20 The difference comes in how the multiple paths to the same disk are=20 handled under linux. If you only have one path to each disk, then this=20 doesn't apply to you. I guess I forgot to clarify if you had more than=20 one path. Anyway, if you have multiple paths mpio knows which is the=20 Active path and which is the Passive path. Sending IO down a passive=20 path will result in IO errors. > Ciao > Daniel > > > > -----Urspr=EF=BF=BDngliche Nachricht----- > Von: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] I= m Auftrag von Kelly Sauke > Gesendet: Donnerstag, 13. Juli 2006 20:04 > An: LVM general discussion and development > Betreff: Re: [linux-lvm] SAN setup with host mirrored disks > > Do the Raiding on the Clariion. Then use either PowerPath or mpio (on=20 > RHEL 4 U3 or newer) to do your failover. If you use md for your=20 > failover layer you may get IO errors on the non-active paths. You need=20 > something that is aware of the clariion setup and that would be=20 > PowerPath or the shipped mpio. > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > =20