HDFS now with Tiered Storage
The eBay tech blog has a post on HDFS’ (relatively new) support for tiered storage. The post describes the feature, which allows a cluster to define different types of storage, and various storage policies that describe how to map replicas to tiers. eBay uses this feature to move much of their data to machines with a small amount of compute power but a large disk density (220TB each).
http://www.ebaytechblog.com/2015/01/12/hdfs-storage-efficiency-using-tiered-storage/
http://www.ebaytechblog.com/2015/01/12/hdfs-storage-efficiency-using-tiered-storage/