EMC is developing an array-based, fully automated storage tiering solution called FAST, which will automate the movement and placement of data based on changing needs. Delivery is promised by the end of 2009 for all platforms. EMC has emphasized the role of flash storage in its storage hierarchy.
Other vendors are already shipping block array-based, tiered-storage solutions. The solutions from vendors such as 3PAR, Compellent, HDS, and Pillar Data are based on a fully virtualized architecture, where the data is split up into small pieces. This allows meta-data on parts of a volume to be captured and the data to be migrated. For example Compellent has already announced and shipped Data Progression™ on the Storage Center array, which automatically and dynamically classifies and moves data at the block level (within a volume) between storage tiers based on frequency of access. 3PAR and HDS offer management tools that monitor and move volumes between storage tiers dynamically. HDS offers the movement of data between heterogeneous arrays. In addition, IBM, EMC, and LSI are shipping appliance-based tiered storage solutions, again based on full virtualization of storage and management tools to migrate the data. All these appliance-based products offer movement of data among heterogeneous arrays.
A key business driver for tiered storage solutions is the growing disparity between cost and performance of different types of storage devices, from SLC flash storage at one end to high-density SATA disk technology at the other. The business case for tiered storage solutions is based on the better utilization of storage resources and the improved ability to meet service level agreements.
Wikibon suggests that an ideal block-based tiered-storage solution would have the following characteristics:
- Allow the definition of cost and performance characteristics of different storage tiers;
- Allow dynamic and non-disruptive movement of volumes and parts of a volume between different storage tiers;
- Allow movement between tiers across a heterogeneous group of arrays;
- Keep historical data on data access patterns and response times at the volume and sub-volume level;
- Provide a rules-based management interface for defining when data should be automatically migrated between tiers, taking into account time, access type, access patterns, and business importance of the applications supported by the storage;
- Allow a manual over-ride of automated data movement decisions;
- Provide management tools to allow the collection of data for monitoring data movement and data performance for use in reporting, charge-back, and storage capacity planning.
Action Item: With validation from EMC, automated tiered storage solutions including flash will turn from a nice-to-have to a basic requirement in 2010. Vendors will need to have their tiered storage solutions ready and tested by then, or they will be drowned by the marketing noise from EMC. Users should start defining their requirements and understanding the business case for their environment, in preparation for assessing and implementing solutions in 2009 and 2010.