LVM Load Balancing

[Smucker]

Our HP Partner was telling me about a HP-UX patch that will allow LVM PVLINKS to do load balancing like PowerPath or SecurePath. He stated there is a patch for 11i and 11.23

Anyone know of such a patch (he did not know the patch number)

[James R. Ferguson]

Hi:

I don't know of any patch that enables pvlinks to perform load-balancing. Rather, I think that your partner is thinking of the Online Replacement patch the enables replacing LVM disks while the volume group is active.

http://www.docs.hp.com/en/7161/LVM_OLR_whitepaper.pdf

Regards!

...JRF...

[A. Clay Stephenson]

I've never heard of such an animal. LVM will implicitly load-balance read operations out of the box but write operations must be completed on all mirrors.

[Amar_Joshi]

hi Clay,

Smucker is not talking about mirror but about the alternate link. I am also in search of such document which says whether load balancing on storage disks' alternate path is possible or not (just with LVM, no SecurePath/PowerPath)?

Does anyone has this information?

[Duncan Edmonstone]

Load balancing will be handled in the mass storage IO stack in 11iv3 (i.e. below the LVM/VxVM layer). So for example, where I might have had /dev/dsk/c3t1d0 and /dev/dsk/c6t1d0 as alternate links to the same LUN, in 11iv3 you will simply have /dev/disk/disk2 and that will be all you need to put in your volume group.

I'm not aware of any changes for 11iv2 or 11i1 which might allow load balancing.

HTH

Duncan