IBM SDD and PowerPath

Question

Can IBM SDD and PowerPath manage different LUNs using the same hba? Currently we have an AIX 5.3 server with 2 hba's. The server has IBM SDD installed and is accessing storage on a DS8300. The customer would like to also be able to access storage from a DMX.

Conor · Accepted Answer

Hey Dynamox, see p264/265 on latest AIX Host Connectivity guide: Supported multiple path IO configurations: - Dedicated HBA's required for Symm devices configured in PowerPathConor

dynamox · Answer

if i am reading this correctly, you can (this is from PowerPath Installation and admin guide found here:

Home > Support > Technical Documentation and Advisories > Software ~ P-R ~ Documentation > PowerPath Family > PowerPath > Installation/Configuration

Coexistence with third-party path management software

PowerPath can coexist with the following third-party path
management software:
◆ Hitachi Dynamic Link Manager (HDLM)
◆ IBM Subsystem Device Driver (SDD)
◆ HP StorageWorks Secure Path
◆ HP StorageWorks AutoPath XP Virtual Array
However, PowerPath cannot comanage devices with third-party path
management software. During installation of PowerPath, the
installation script tests for the presence of third-party path
management software on the system. If such software is installed on
the system, the PowerPath installation script disables support for the
corresponding array type in PowerPath.

nystrole · Answer

'However, PowerPath cannot comanage devices with third-party pathmanagement software'Does this mean that PowerPath and the third-party cannot comanage the same LUN OR the same LUN and same HBA?

dynamox · Answer

can not comanage the same array. So if if PowerPath detects that you have SDD driver installed on the system and it's used to manage DS array, PowerPath will not try to manage the DS, it will only manage the DMX. PowerPath manages storage not HBAs.

Conor · Answer

Just to expand on this, PP and SDD can coexist on the same host, as long as the arrays they manage are on separate HBA's. So you can have EMC Storage/PP on one pair of HBA's and IBM Storage/SDD on the other pair.

Conor

dynamox · Answer

Conor,where is that documented ?

Conor · Answer

I don't have alot of experience on the Windows side, but I know the reasoning for not recommending mixing vendor storage on the same HBA's is due to each vendor having slightly different recommended HBA configuration parameters.

Now if both vendors had exactly the same HBA config recommendations, then I could not see a reason for it being a problem sharing the HBA's... agreed?

dynamox · Answer

Thanks Conor ..this HBA limitation ..is this only for AIX and only for SDD/PowerPath ..how about Hitachi HDLM ?

dynamox · Answer

the reason i ask is a few years back i was supporting windows boxes that were connected to Hitachi UPS and DMX. The systems were running HDLM and PP and EMC had no problems supporting the box even thought there was only one pair of HBAs. Just curious ..

Conor · Answer

The generic recommendation would be not to mix different storage vendors arrays' on the same HBA's. Regarding your question specifically, I'll look into it and get back to you... Conor

dynamox · Answer

Hitachi had slightly different settings from EMC (we were using EMC settings) but it did not stop Hitachi from supporting the box.