From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Smart Subject: Re: multipath and san fabric Date: Mon, 13 Nov 2006 14:54:15 -0500 Message-ID: <4558CD67.6000104@emulex.com> References: <4558C4E9.9020901@emulex.com> <6CCEAEDF4D06984A83F427424F47D6E4013D153F@CORPUSMX40A.corp.emc.com> <20061113195227.GE13788@vienna.egenera.com> Reply-To: James.Smart@Emulex.Com, device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20061113195227.GE13788@vienna.egenera.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: "Philip R. Auld" Cc: device-mapper development List-Id: dm-devel.ids Yep - Ed caught my typo.... :) -- james Philip R. Auld wrote: > Rumor has it that on Mon, Nov 13, 2006 at 02:39:08PM -0500 Edward Goggin said: >> You may want to also cross connect across the 2 target >> controllers (A,B) in case 2. Doing so provides more >> redundancy for asymmetric arrays and better resource >> utilization in case of a failure of either an HBA or >> target controller which would otherwise prevent >> utilization of the other HBA or target controller >> for that LU when load sharing I/O across multiple >> paths. >> >> So the I_T nexus's for the 4 paths are: >> >> HBA1_TargetPort1 >> HBA1_TargetPort3 >> HBA2_TargetPort2 >> HBA2_TargetPort4 >> > > That's exactly what James's example 2 describes. It's just > typo'd in the DM paths list. > > > >>> -----Original Message----- >>> From: dm-devel-bounces@redhat.com >>> [mailto:dm-devel-bounces@redhat.com] On Behalf Of James Smart >>> Sent: Monday, November 13, 2006 2:18 PM >>> To: jslittl@hendricks.org; device-mapper development >>> Subject: Re: [dm-devel] multipath and san fabric >>> >>> If the hba's are on different fabrics - why would you ever put an hba >>> that is not in the fabric in a zone in that fabric ? (e.g. >>> your second >>> option makes no sense). >>> >>> If you are stating that the 2hba's are on different fabrics >>> (and in zones >>> within those fabric) - but they are seeing the same Storage >>> device on both >>> fabrics - then the dm config (note: I'm not talking about >>> zoning anymore) >>> would have a path per I_T nexus. I state it this way to >>> account for dual-ported >>> controllers, which may appear as separate targets, may exist >>> within the fabric. >>> >>> Example 1: >>> Fabric A contains HBA1 and TargetPort1. Typically a zone >>> would exist >>> within Fabric A that contains these 2 ports. >>> Fabric B contains HBA2 and TargetPort2. Typically a zone >>> would exist >>> within Fabric B that contains these 2 ports. >>> The storage array contains 2 controllers with 1 port per >>> controller, or >>> is a single controller with 2 ports. Either way, the two >>> ports are >>> TargetPort1 and TargetPort2, are on the same array, and >>> all storage >>> can be seen from any port. >>> -- >>> This would have 2 DM paths. >>> The I_T nexus's are: >>> HBA1_TargetPort1 >>> HBA2_TargetPort2 >>> >>> Example 2: >>> Fabric A contains HBA1, TargetPort1, and TargetPort3. >>> Typically a zone >>> would exist within Fabric A that contains these 3 ports. >>> Fabric B contains HBA2, TargetPort2, and TargetPort4. >>> Typically a zone >>> would exist within Fabric B that contains these 3 ports. >>> The storage array contains 2 controllers, with 2 ports per >>> controller. >>> Meaning TargetPort1 and TargetPort2 are on controller A, >>> and TargetPort3 >>> and TargetPort4 are on controller B. The ports are cross >>> connected on >>> the fabrics for redundancy. All storage can be seen from >>> any port. >>> -- >>> This would ahve 4 DM paths >>> The I_T nexus's are: >>> HBA1_TargetPort1 >>> HBA1_TargetPort2 >>> HBA2_TargetPort3 >>> HBA2_TargetPort4 >>> >>> -- james >>> >>> John Little wrote: >>>> Hi all >>>> >>>> Admittedly this is not the correct forum for this question >>> but I have googled >>>> this and the only people I have to ask around here are >>> people who won't touch >>>> it because it is Linux. >>>> >>>> My question is this: I'm using SLES10 with two emulex >>> hbas, one connected to >>>> fabric a and one to fabric b. When zoning the switch for >>> the hbas do I put >>>> in only one path to the fabric per hba or do I put in two, >>> one to each of the >>>> separate fabrics? >>>> >>>> Again I realize this is not exactly the correct forum but >>> since I couldn't >>>> find an answer anywhere else I figured you guys would be the most >>>> knowledgeable. If there are some docs somewhere that you >>> could point me to I >>>> would appreciate it. >>>> >>>> John >>>> >>>> -- >>>> dm-devel mailing list >>>> dm-devel@redhat.com >>>> https://www.redhat.com/mailman/listinfo/dm-devel >>>> >>> -- >>> dm-devel mailing list >>> dm-devel@redhat.com >>> https://www.redhat.com/mailman/listinfo/dm-devel >>> >>> >> -- >> dm-devel mailing list >> dm-devel@redhat.com >> https://www.redhat.com/mailman/listinfo/dm-devel >