[robby]

Hey Folks,

I'm new to the forum and making my first post so bear with me.

I need some help with Boot from SAN, HDLM and MPIO.

System config:
P550, AIX 5.3, 2 FC HBA's connected to a 9990 HDS SAN. Existing multipathing software is HDLM

The problem:
As far as I understand from the HDLM docs the rootvg disks shouldn't be managed by HDLM. hdisks making up the rootvg are entered into the dlmfdrv.unconf file to tell HDLM not to configure them as virtual HDLM devices(dlmfdrvXX).
So what then manages the root disks in case of say a switch failure? Recent testing has shown the disk will become missing to the volume group and not autorecover even if the disk becomes available again after the switch fault is repaired. (In our testing we disabled the switch port) This I prety much expected.
Can MPIO help there? Will it live happily with HDLM or will the two pieces of software utlimately conflict with each other?

Does anyone have any better solutions for getting boot from SAN to be more resilient?

[Frans]

I find that having boot disks like disk may be beter to do via a vio-server

[robby]

Thanks Frans,

VIO isn't an option right now. I dug a little deeper into this with IBM and HDS/SUN. HDLM v5.9 apparently provides support for boot disks among other things.

HiCommand Dynamic Link Manager (for AIX) 5.9.0-01 New Features and Enhancements

[5.9.0-00 Additional Functions and Modifications]
(1) Environment in which the MPIO device can be managed by HDLM are supported.
(2) Environment in which the boot disk can be managed by HDLM are now supported.
(3) Command Device, Swap Device, and Dump Device have been added to the supported storage subsystem of Hitachi.

I hope to get my hands on this version soon and will install and test and post any findings here.

[cccompton]

Robby,
We are in the same situation you describe here. Did HDLM v5.9 work for you? If so, could you outline the steps you took to configure the boot disks?
Thanks,
Chris

[jrigler]

Ironically the new HDLM is integrated into mpio in a way that it didn't used to
be. Now on our systems, we see only one hdisk for each LUN and it shows up with paths in mpio AND we have a HDLM command that I don't remember that also shows info.