The New EC2 High Storage Instance Family : Stakes and Opportunities for applications and Organizations.

Available since December 21, 2012, The New EC2 High Storage Instance Family marks the Amazon quest to ensure more or less that Amazon EC2 is applicable to an incredibly broad array of use cases.

The High Storage Eight Extra Large (hs1.8xlarge) instances targets applications that require high storage depth and high sequential I/O performance. Each instance brings and includes: 117 GiB of RAM, 16 virtual cores (providing 35 ECU of compute performance),

and 48 TB of instance storage across 24 hard disk drives.

some nmon output with all of the disks visible

We learn that, the storage on this instance family is local, and has a lifetime equal to that of the instance. You should build a degree of redundancy into your storage architecture (e.g. RAID 1, 5, or 6) and you should use a fault-tolerant file system like HDFS or Gluster , back up your data to Amazon S3  and you can launch multiple High Storage Eight Extra Large instances in a placement group for high bandwidth ,low latency networking between the instances.

Available henceforth in the US East (Northern Virginia) Region and will be made available in other AWS Regions as soon as possible. However you can see the EC2 pricing page for more information.