Question About V-Max

Was just thinking through some of the newer storage tech today while driving to and from a customer.  It is widely expected that HDS is going to announce the availability of their clustering of the USP-V line of boxes tomorrow.  We know that the technology has been built into the microcode and hardware since the release of the box so I don't think it's going to be a huge surprise. 

So I got to thinking about the V-Max and how it's cache a disk is managed.  I haven't read too many of the manuals yet, so I thought I'd ask here since I know the EMC guys read this blog.

  • What sort of traffic is traversing the RapidIO network today?  Is it just management traffic or is IO actually being sent from one engine to another?
  • If IO is sent to one engine but the LUN is managed by another engine then how is cache coherency managed?  Is the cache one large pool or does each engine have it's own cache?
  • Are the LUNs addressable in an active/active fashion as the DMX-4 and USP-V are handled today?  e.g.  Can an IO be sent to multiple engines at the same time in a true active/active fashion?  We're not talking about Clariion "active/active" here.  ;-)

Here is the way I kind of see it.  Each engine manages it's own set of storage and forward IO to the other engines as needed.  Is that right or wrong?  I'm looking for an education here, so please help me out.  To me it seems like since each engine has it's own FE and BE ports that the BE ports must have a specific set of disks attached to them.  Right?