Excellent article. I think the network bandwidth issue is really important and often overlooked. It is mentioned in the article, but I'd add that a WAN circuit of even just moderate bandwidth can cost as much per month to operate as some disk drives cost to buy. And can easily cost significantly more. So if you are syncing to a DR site, getting the backup image over there, and as mentioned, log shipping or replication, can take a big byte out of it. Bandwidth is also not something you can quickly address if you run out of it! Disks are usually a two week turnaround to buy more and rack them up. WAN circuits are running 120 days or more!