Sunday, April 26, 2009

This is a very interesting concept and reduces costs even further than standard FCoE does.  If you are intrigued by FCoE, but are intimidated by its cost, consider this: what if you put a few FCoE cards in the IO controller and shared those across multiple servers? The result would be a significant reduction in cabling and no need for a top of rack switch, you could just run your FCoE connections out of the Aprius IO controller to the end of row switch.

This applies equally well to deploying 10 Gb Ethernet to a bunch of servers.  Instead of placing a separate 10 GbE card in each server just share a few 10 GbE cards in the IO Controller.  Just as with FCoE, this provides a low cost way to get started with the newest high speed IO technologies.

Another dimension on consolidation that the IO Controller provides is  in being able to share a specialized card across multiple servers as the designated ‘backup’ card.  For example you might have two compression cards in each of several servers for an application; one for primary use and the other as a failover card for redundancy.  This could get expensive if you have a redundant card that will rarely get used in each server.  Instead you could place a single redundant  card in the IO controller and then if there is a card failure in any participating server, the affected server rescans the IO Controller's bus to pick up the second card inside the IO controller. N+1 rather than 2N.

So how exactly do you share multiple cards with multiple servers?.  The first step in this process is using cards with multiple ports. For example a 4 port FC card.  You can hard set each server to a particular port.  One 4 port card is less expensive than four 1 port cards so the economics make sense.

The next step is to have multiple servers share the same port on the same card.  To make this work is going to take some advancement on the part of card manufacturers.  The good news is that much of that development work is already done and card manufacturers need to simply add support to the cards. There is a technology called Single Root IO Virtualization (SR-IOV) that many HBA and IP NIC card manufacturers have committed to putting into their next generation cards, although both Neterion and Intel have the cards available now.

With SR-IOV you will have the ability to have up to 256 virtual functions per card.  This means that a single SR-IOV enabled FCoE card placed in the Aprius IO Controller could have multiple servers accessing it simultaneously, dramatically reducing costs and maximizing available bandwidth.

A part of this will be a NIC level QoS which will allow prioritization of the virtual functions to make sure that critical servers have the best access to bandwidth when they need it.

The Aprius IO Controller is a switch that allows for intelligently sharing PCIe cards across servers.  The impact of this could be to assist in the adoption of new technologies like FCoE at an even lower cost point than what FCoE proponents currently envision.