On Wed, Sep 24, 2008 at 3:46 AM, Tom G. Christensen <[EMAIL PROTECTED]> wrote: > D Canfield wrote: >> >> IBM DS4000's (and some Clariions and a few others as I understand it) >> use an active/passive setup, so only one path can own a given SAN LUN at >> a time. If you were to use round-robin to access a single array across >> two HBA's, you would would thrash the SAN controller because it would be >> constantly switching ownership of the LUN back and forth between this >> SAN controllers rather than sharing the LUN like an active/active array >> would. >> > Load-balancing does not have to be between the controllers on the array. > > In a typical EMC Clariion setup you'd have up to 4 uplinks pr. controller > (SP) spread out between two fabrics. > Each client then has two HBAs, one connected to each of two fabrics. > What DM-MPIO allows is for the client to load-balance access across both > fabrics against the active SP on the Clariion. > To keep a single SP from being overloaded you would then spread ownership of > the exported luns out between SPA or SPB on the Clariion.
I don't understand how this relates to the fact that the Clariion has a "preferred path" and freaks when the connection isn't on that path. I'm not clear on how dm-mpio is at all aware of the preferred path. That's a reason we've always recommended PowerPath, because it seems to have that intelligence built-in. If it's not too much, can you detail the required (host side) config bits a little more? I understand that on the Clariion side you simple assign across both controllers.... Don _______________________________________________ rhelv5-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv5-list
