SAN/LAN/WAN convergence day two

In part two of our look at SAN/LAN/WAN convergence, we consider why you would want to converge.

But what about the other reason for SANs - separating storage traffic from other network traffic? "If we have a look at the traffic on the network scenario, when we're setting up networks today, we typically set them up such that there are segregated networks for different types of traffic anyway and we do that in with VLANs," says Dimension Data's Ronnie Altit. "Nothing changes in a storage area network that you're implementing with IP insofar as you would have segregated VLANs such that the traffic that's there doesn't cross other networks. Yes, it will share the same back plane on your switches. But again, the back plane that's on Ethernet switches today is more than capable of handling additional storage traffic requirements."

Due to the high cost of implementing a fibre channel SAN, getting almost the same results with ordinary switched Ethernet is particularly appealing in development and testing environments. "IP-based SANs open up opportunities to connect up servers that you otherwise might not want to put on a SAN simply because of the connectivity cost of entry," says Altit. "You may now be able to add to your SAN and start to reap the benefits of SAN technology insofar as snapshots and point in time clones and those sorts of things within your development environment."

Indeed, that makes a lot of sense, and when you're testing new applications, you no longer have to find a downtime window on your production servers or spend a considerable amount of money on your test servers just to join the SAN party. "If you take the average costs of connecting a server into the SAN, just a single point connection, it's probably going to cost you about $2,500 per server just to provide connectivity to the storage area network if you're basing it on fibre channel," says Perera. "If however, you're going to base it on IP where you're just using a standard LAN network card, then the costs is significantly reduced and accordingly the barriers to entry start to be removed."


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