Hi everyone,

I have some questions for the experts regarding a SAN configuration.

Configuration: FAS3020c MetroCluster (2 sites, 16km distance) 2 FC-Switches on each site, each connected via ISL's to the other location. 1 RHEL ES4 U5 Host on each site with a 4GB QLogic Dual Port HBA. Each FC-Port on each Host is connected to one of the switches FCP enabled and the cf mode is single image Snapdrive for Linux on both Hosts.

Following situation: Snapdrive for Linux currently does not support DM-Multipathing on RedHat Linux. We have an open case with Netapp and they are working on the issue to support mulipathing (planned for Q1/08)

When I started I setup everything for multipathing because we thought the support for it would be released earlier. I zoned the switches... Zoning: switch1 zone1: 0b(filer1)+0b(filer2)+port0(host1) switch1 zone2: 0b(filer1)+0b(filer2)+port1(host2) switch2 zone1: 0d(filer1)+0d(filer2)+port1(host1) switch2 zone2: 0d(filer1)+0d(filer2)+port0(host2)

On the host I implemented DM-MP and use the mpath-Device's to access the LUN's on the cluster. Each mpath-Device consists of 4 sdx-Devices(=the 4 paths to the LUN). Example: mpath0 (360a98000433464706334455142706e33) [size=100 MB][features="1 queue_if_no_path"][hwhandler="0"] _ round-robin 0 [enabled] _ 3:0:1:0 sdd 8:48 [active][ready] _ 4:0:1:0 sdf 8:80 [active][ready] _ round-robin 0 [enabled] _ 3:0:0:0 sdc 8:32 [active][ready] _ 4:0:0:0 sde 8:64 [active][ready]

This is working fine. The customer already installed his Oracle RAC on the LUN's/mpath-Device's which where presented to the host's.

And here my problem: The customer can not wait until Q1/08 when Snapdrive for Linux supports multipathing on RHEL and I have to redesign the SAN to a single path configuration so SnapDrive is working and supported. My questions: Can I just use the sdx-Devices on the linux host's and leave the zoning and multipathing as it is? Will the cluster failover then work correctly? Or should I deactive multipathing on the hosts and just zone one hba port to one filer fc port and use that sdx-Device?

I will have to implement multipathing for sure later when it is supported with linux and snapdrive so I prefer minimum or no changes to the current configuration :) Has anyone experience with such a problem/configuration?

Thankful for any tips & hints!

Best regards, Alexander

-- Alexander Schalek, Technical Services / IT-Infrastruktur Bacher Systems EDV GmbH FN 54202i, Handelsgericht Wien Clemens-Holzmeister-Strasse 4 A-1100 Wien, Business Park Vienna, Austria phone: +43 (1) 60 126-34 | fax: +43 (1) 60 126-4 e-mail: as@bacher.atmailto:as@bacher.at | web: www.bacher.athttp://www.bacher.at