From your first question you asked if “how to get that spare server take over the job incase one of the active server fails”. This can be done from our Volume Replication (iSCSI Target) feature where the Source Target is active. If Source has failed and “spare server take over” then Destination server of the mirrored Source Volume being replicated would take over as Source. The iSCSI servers would have their own independent storage from the FC Storage backend and can utilize MPIO. Each iSCSI server would have its own storage but currently you can have only 1 to 1 relation with our Volume Replication – meaning Server A (has a value size of xxxTB or GB for designated target volume) to Server B (has an equal value size of xxxTB or GB for designated target volume) only for Source to Destination. So if Source fails then Destination will become Source and the mirrored iSCSI Target Volume from the failed Source will be available by enabling the Target for the promoted new Source Server. The time to do this would be very short (several clicks to enable this). We do not have this documented with Xen virtual machines for your specific inquiry, so this is why I was providing you the 30 day evaluation of our software to perform some test as most of our enterprise customers do this in a simulated test lab to assist their process. The only way to share the same capacity pool would be to have DSS on the front end and use the iSCSI initiator to access the iSCSI-R3 servers on the back end then create a Volume group (using Software RAID) from the 2 iSCSI-R3 servers. You may feel free to contact us on pre-sales questions at T: +49 (89) 800777-0 for UK territories or 770-881-7680 for North America territories.