This morning I got very excited. While quickly scanning the headlines of the 1000+ unread feeds that had accumulated in my Google Reader this week, one heading in particular caught my attention, “Amazon Elastic Block Store goes live!“.
The post from the Right Scale folks gives a detailed overview of the new Amazon ‘SAN storage in the cloud’ service, aka Elastic Block Store, aka EBS. Alas, this particular cloud offering was a mirage, the post was subsequently removed (but can still be viewed on Robert Scoble’s Shared Items) it seems the post was a work-in-progress and not intended for publishing, yet!
Why was I so excited? Amazon EC2 had two major shortcomings when it launched 2 or so years ago; the first, ephemeral IP addresses, was solved by the new Elastic IP feature; the second, ephemeral storage volumes (when you shutdown an instance the disks are wiped!) is due to be solved by EBS. With both of these problems solved, EC2, already near perfect, would be perfect.
The article does a good job of explaining the new service…
EBS starts out really simple: you create a volume from 1GB to 1TB in size and then you mount it on a device on an instance, format it, and off you go. Later you can detach it, let it sit for a while, and then reattach it to a different instance. You can also snapshot the volume at anytime to S3, and if you want to restore your snapshot you can create a fresh volume from the snapshot.
The thing that caught my eye in the above paragraph was the snapshot facility. Snapshots are to be stored on S3 via an EC2-specific incremental-snapshot API. This means the volumes will come with a built-in back-up facility. This is important as EBS drives reside in one availability zone (that of the instance that they are mounted against) and do not have the data replication security offered by S3. It also means that disk systems can be restored quickly and simply from snapshots without the overhead (and bugs!) of writing an S3 specific incremental backup and restore utility.
Back to waiting…
UPDATE: 20th August