January 13, 2014attribute reaches a certain value, and (3) action events that occur when actions such as data insertion or deletion are performed. There are many responses that Tiera instances would eventually need to support. Table I shows some of the basic responses currently supported by our Tiera implementation: store data in a tier, retrieve data from a tier, move data between tiers, copy data from one tier to another, and delete data in a tier. Tiera also supports advanced responses: storeOnce, grow/shrink, compress/decompress, and encrypt/decrypt. Other responses that will be added to Tiera in the future include object versioning, journaling, transactions, and data snapshotting. Tiera’s design is highly modular making it very easy to add a new response 2. In Section II-C we will show how a rich array of data management policies can be easily constructed using these event-respons
