[Linux-cluster] GNBD with multiple iSCSI initiators

[pheeh at nodeps.org]

I have a question about the multipath functionality that I can't seem to
find from the RedHat documentation.
I've only configured GFS for use with a single GNBD server which exports
local drives.
The goal in this configuration is to use 4 machines, 2 GNBD servers and 2
Storage servers.
The theory I have is the following:
Export one partition on each storage server via iscsi to the GNBD servers.
Use multipath to direct traffic between the two iscsi devices.
Configure the two GNBD servers for use in a fault tolerant environment.
The question comes in when figuring out hwo GNBD multipath will direct
traffic.
would i have each gnbd server offer out an individual iscsi initiator from
one storage server?  would i have each gnbd server offer out both iscsi
initiators?
would gnbd handle the data syncing between initiators to ensure that
storage servers both have the same data?
would i have one or two lvm's with this setup?
the documentation of gnbd and iscsi seems a bit sparse...the redhat manual
seems like it glazes over the subject.
when i purchase the subscription do i get more GFS documentation?  kinda a
catch 22 in that case since i hvae to get the proof of concept runnign
before i can get the budget approved :(