Friday, 13 April 2007

AoE/FCoE/iSCSI

Robin harris discusses AoE from Coraid. I looked at this last year (reminder) as I saw it as a great way to get a FC/iSCSI solution at a low cost. However, before everyone rips out their FC SANs and runs to put an Ethernet solution in place, take one step back and consider the issues. Fibre Channel is successful because it works; because it is reliable. FC switches have features such as non-blocking architecture, QOS, preferred path and so on which help to remove or eliminate throughput or performance issues. Would ATA over Ethernet (or for that matter as it seems to be a topic of the moment) FC over Ethernet provide for that level of switch point to point bandwidth guarantee?

Consider also your monitoring tools. Both Brocade and Cisco offer features to do traffic redirecting (e.g. SPAN ports) to easily analyse SAN traffic without putting TAPs in place. Will AoE and FCoE offer that?

Consider security. Will AoE provide the same level of security as FC?

Without a doubt, you get what you pay for; however you should only pay for what you *need*. If you are running a mission critical application FC is still the best option - interoperability is more widely tested; diagnostic tools are mature; the technology is reliable. I do think there's a place for AoE, iSCSI and FCoE, but use it in the wrong place and what you save in cost, you may pay for later in downtime.

2 comments:

John Morganti said...

When trying to choose between Fibre Channel and iSCSI, if the iSCSI solution under consideration is EqualLogic, the choice is a no-brainer.

Not only does EqualLogic's PS Series outperform EMC's Clariion (and cost less money), it's also unbelievably easy to setup and manage. With EMC, a team EMC techies arrive onsite to help you get set up. With EqualLogic, one IT resource with 20 minutes can unpack, rack, and configure this array. It's that easy!

Did you buy the extra software and support contract for remote replication with your EMC? With EqualLogic's PS Series, each array includes:
=> remote replication
=> snapshots
=> automatic load balancing
=> volume cloning
=> Add more disks, controllers, and arrays without any service interruption.

And the best part is, the array and all its features are covered by one simple, reasonably priced, support contracts. If you've got 3,4, and 5 support contracts on your EMC array, wouldn't you prefer to have 1 support contract for the entire array? You don't buy a car one feature at a time, why would you buy an array that way?

My advice to EMC users: Replace your old equipment while you still can. EqualLogic is eating up the market.

Just look at what these folks have to say:
http://27signposts.blogspot.com/2007/03/emc-plays-catch-up-with-clariion.html
http://27signposts.blogspot.com/2007/03/one-cios-choice-between-iscsi-and-fibre.html
http://27signposts.blogspot.com/2007/03/equallogics-iscsi-san-hits-storage.html
http://27signposts.blogspot.com/2007/03/iscsi-san-advantages.html

michaelian said...

AoE is ethernet. Cisco's port spanning features just work with it out of the box. Just as you don't need a special NFS, or SMB feature to mirror traffic in the switch.