SG/LX and Multipathing

[ca14]

I'm running SLES10 and and would like to use the multipath/MPIO software for the SAN.

I have Hitachi USP storage with Qlogic HBAs and as far as I know this storage is not supported with ServiceGuard. According to Novell the SAN and HBAs are supported with MPIO ... So my question is does ServiceGuard support the use of MPIO ?

[Matti_Kurkela]

There are various ways to handle the multipathing with Linux.

If you use the multipath feature of the Qlogic HBA drivers, the answer is yes: ServiceGuard is supported and needs no special configuration to use it.

if you use the /dev/md* -style multipathing (as in Linux 2.4 kernel series) or the new device-mapper multipathing, the answer might be along the lines of "not supported, known to work". On the other hand, the situation may have improved since I last checked: read the release notes of your SG/LX version to be sure.

MK

[Andrew Prolisko]

If it's the multipath within the Qlogic driver then see "HP StorageWorks Using the Qlogic HBA Driver for single-path or multipath failover mode on Linux systems appication notes" Part number: AA-RVGWG-TE Sixth Edition: July 2006.

If it's device mapper multipath see: "Device Mapper Multipath Configuration Guide for HP StorageWorks Arrays" Part number: AA-RW8RB-TE Second editon: December 2006. Also useful is Novell Knowledgebase article "How to setup/use multipathing on SLES". You will find that an extensive list of storage arrays are supported including some Hitachi ones. It is imperative to have the latest multipath/udev patches installed.

Both of the above multipath methods are supported by Serviceguard. See "Servicegaurd for Linux Version A.11.16 Release Notes - Using udev for Persistent Device Names" (page 23).

If you are intending to use a quorum disk with device mapper multipath enabled,you will probably need to blacklist the quorum device in the multipath.conf file.

[ca14]

thanks very much for the replies - apologies also for my unclear definition of the MPIO technology. The MPIO I was referring to is the multipath-tools delivered with SLES10 ...

Ideally we would like to use the serviceguard extended distance cluster software with the Multipath based SAN setup ... but it seems unclear if this would be supported. Whats the official line on that ?