SANs in the cloud

Amazon has publicly released a new Amazon web service called Elastic Block Store providing up to a terabyte per volume of persistent storage and allowing you to run your database in their cloud with the advantages of snapshots and flexible attachment to servers.

Rightscale, who offers a management and automation system based on AWS, has an excellent article explaining how Amazon’s Elastic Block Store works. In testing they report over 70 MB/s (that’s over half a gigabit per second) and over 1000 IOPS or input/output operations per second which is the ballpark equivalent of a dozen 7200rpm hard drives serving your data in tandem. They also report “it is possible to mount multiple volumes on the same instance such that file systems of 10TB are practical.” No doubt much more detailed performance and feature analysis will ensue shortly.

Om Malik covers this huge development for AWS and suggests that data centers should be concerned. I agree that data centers and hosting companies who cater to small customers that can retool quickly and take advantage of the cloudSAN services may lose some business to Amazon, but I doubt this will slow the huge growth in demand for high quality multi-tenant data centers. That said, a big shift in the datacenter ecosystem is almost certain.

Aside from the obvious obstacles some businesses would have to running their database storage in the cloud (there’s something to be said for being able to drive down to your data center with a crowbar and carry away the physical magnetic fields that encode your data), the big question mark about this service will probably surround the OPEX (operational expenses) associated with running your database in the cloud and just how effectively it offsets the evaporation of CAPEX (capital expenses) since you no longer need to buy a SAN.

Amazon provides the following example: “a medium sized website database might be 100 GB in size and expect to average 100 I/Os per second over the course of a month. This would translate to $10 per month in storage costs (100 GB x $0.10/month), and approximately $26 per month in request costs (~2.6 million seconds/month x 100 I/O per second * $0.10 per million I/O).”

S3 snapshot storage and EC2 server costs are not included. We’ll keep you posted.