Originating author: David Vellante
Today, January 14, 2008, EMC announced several important enhancements to its Symmetrix DMX plaftorm. The two most notable improvements are:
- The announcement of support for 73GB and 146GB flash devices within DMX-4;
- Support for Virtual Provisioning, EMC's version of thin provisioning.
Flash drive support is only available on DMX-4's, however all other enhancements are available on both DMX-3 and DMX-4 lines, including Virtual Provisioning, 1TB SATA drive support, better efficiency on SRDF for multi-site replication and other mainframe enhancements. General availability for these improvements is March 19th.
The incorporation of flash-based solid state disk (SSD) drives into DMX-4 introduces what EMC refers to as Tier 0 storage offering 10X response time improvements relative to mechanical disk drives. Candidates for this class of storage are clearly high performance, high volume transaction processing applications. Examples EMC cites include currency exchange, electronic trading systems and real-time data feed processing but there are many others. EMC is OEMing a customized version of the flash device from STEC, Inc.
Notably, this performance boost comes at a cost. On a head-to-head device comparison with conventional FC disk drives, EMC's flash technology will command a hefty 30X premium. But as Fred Moore points out in A brief history of solid state disks these are not the right metrics for understanding SSD. Moreover, EMC stresses that many customers are inefficiently deploying conventional devices today and on balance, expect a typical DMX-4 configured with flash devices to command about a 10% premium. If that's the case, customers should strongly consider this technology for candidate applications.
SSD has come full circle at the high end. Once a vibrant market, the introduction of Expanded Storage by IBM and the popularity of cache-based disk architectures all but killed adoption. Ironically, EMC was an early SSD innovator as an OEM supplier to StorageTek and many of the company's early perspectives on mainframe storage were seeded with experiences from the customer access it gained through the STK relationship. While the incorporation of flash will help EMC's green-ness the real motivation for this innovation is performance. By integrating flash technology into the DMX-4 architecture, customers benefit from full exploitation of the many software capabilities inherent to DMX such as local and remote replication and now, Virtual Provisioning.
EMC's Virtual Provisioning announcement was widely anticipated as Hitachi's thin provisioning got the jump on EMC at the high end and 3PAR has been shipping for years in mid markets. Thin provisioning will not only provide EMC customers with the commonly understood benefits of the technology, but customers of the new flash devices can utilize Virtual Provisioning to maximize utilization of this expensive resource. EMC claims its implementation of thin provisioning can reduce provisioning times to a greater degree than Hitachi's implementation. The company provided comparisons with its own DMX-5771 and -5772 as well as with Hitachi. The data showed substantial improvements with EMC (e.g. up to 6X, 2X and 2X faster provisioning respectively).
EMC has indicated that Virtual Provisioning may be used to simplify provisioning for both thin and traditional 'fat' volumes. To provide some context here, to initially provision storage, customers must go through about nine steps (for both fat or thin volumes). Over the past several years, EMC has reduced this process from an hour to to about ten minutes today. This process creates a pool of either traditional 'fat' volumes or thin volumes. To add storage to an application that has fat provisioned volumes, you need to go thru another 10-minute, 9-step process. To add capacity to a thinly provisioned application customers go through a 2-step 30 second (approximately) process to make storage available to the target pool.
EMC's approach appears to be on the cutting edge of simplicity at the high end. Customers should nonetheless be prudent with thin provisioning and understand the caveats before investing. There are several best practices customers should consider when contemplating thin provisioning from any vendor. As well, customers should take into consideration the additional acquisition costs of thin provisioning. Virtual Provisioning will alleviate much of the add/change/move challenges EMC DMX customers report today, however it won't solve all problems, especially those related to time-consuming migrations. As such, virtualization technologies from EMC (Invista) and others (e.g. Hitachi and IBM) will remain viable.
Action Item: EMC continues to make incremental improvements to its DMX architecture by delivering tangible, tactical benefits to customers. The inclusion of SSD goes beyond that and is an innovation which will likely set off a chain reaction in the industry. Storage organizations should analyze which data sets are candidates for SSD and apply the technology but only where the economics are compelling to business lines. EMC's imprimatur has been stamped on thin provisioning at the high end of the storage marketplace. On balance customers with large amounts of DMX storage will be well served with in-box tiering that accommodates tiers 0, 1 and higher. Customers with a more diverse base of installed storage assets should continue to investigate virtualization engines from EMC and others as part of their strategy.
Footnotes: EMC flash announcement