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@xxxxxxxxxx > > [mailto:dm-devel-bounces@xxxxxxxxxx] On Behalf Of James Smart > > Sent: Monday, November 13, 2006 2:18 PM > > To: jslittl@xxxxxxxxxxxxx; device-mapper development > > Subject: Re: 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@xxxxxxxxxx > > > https://www.redhat.com/mailman/listinfo/dm-devel > > > > > > > -- > > dm-devel mailing list > > dm-devel@xxxxxxxxxx > > https://www.redhat.com/mailman/listinfo/dm-devel > > > > > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel -- Philip R. Auld, Ph.D. Egenera, Inc. Software Architect 165 Forest St. (508) 858-2628 Marlboro, MA 01752 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
