[libvirt-users] Multipath pools - practical for use?

[Justin Clift]

Hi all,

Writing up some Fedora documentation, and looking to figure out the best 
way of mapping multipath network(!) LUNs to pools in libvirt.

   ie Infiniband SRP LUNs, but would probably apply to Fibre Channel
      equally as well.

There are two approaches I can think of easily:

  a) Large LUNs (ie TB+) that are mapped to a host server as disk, with
     each LUN being configured as an LVM pool.  This lets the host
     slice the pool up into volumes with the libvirt volume creation
     commands.

  b) Pre-purposed LUNs mapped to a host server as disk, but passed
     through directly to their respective guests.

     ie Something like Oracle, with 3 SAN LUNs mapped to guest FOO for
        its database data

In a non-libvirt world I'd look at configuring the LUNs on the host
with persistent name using multipath, then present them appropriately to 
whatever needs them from there.

However, libvirt has a pool type called "multipath".  Looking at the 
docs online, it doesn't appear to be all that fully featured at this 
point.  Seems more of a brief mention and footnote, so I'm wondering 
whether to use it or skip it for now in the Fedora docs.

Anyone have thoughts/suggestions/etc? :)

Regards and best wishes,

Justin Clift

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