Moderator: David Floyer
Analyst: David Vellante
[Editor's Note: In January 2008, EMC announced Dynamic Provisioning (its version of thin provisioning) for the DMX line of products. Many of the concepts in this note still apply.]
Hitachi and its distribution partners Sun and HP have announced four features with meaningful implications:
- Improved performance,
- Thin provisioning of external devices,
- Availability of 750 gigabyte SATA II drives in the bay and,
- Support of virtualized externally attached arrays with non-disruptive application data mobility between servers and storage tiers by VMware's ESX Server
Of these, performance and thin provisioning of external devices are the most interesting. While Hitachi made no changes to its previously published SPC-1 benchmarks for the USPV, it did announce increases to theoretical maximum performance of 22%. This is a notable improvement, although at this time it is unclear exactly how that improvement has been achieved. The previously published SPC-1 benchmarks showed that USPV supports sub-5 millisecond response times, which implies that performance is constrained by the lack of disk drives rather than lack of controller bandwidth. It appears more performance is there and perhaps available to drive the second key feature in the announcement, external thin provisioning. However this has not been substantiated by Hitachi, and users should push Hitachi to provide visibility on the performance of externally thin provisioned volumes and clear guidelines on where thin provisioning is appropriate and where it is ill-advised.
In May, Hitachi announced thin provisioning within the array. On November 5, 2007, it announced that it had extended thin provisioning to external arrays, meaning thin provisioning can be applied to heterogeneous arrays in a data center. Arrays supported and qualified include products from EMC, HP, IBM, LSI, Sun and Hitachi's own midrange systems. This is a unique capability that theoretically can be combined with virtualization across multiple arrays. The critical questions the Wikibon community posed are: Do the functions work, and what are the adoption and migration costs?
Hitachi claims more than 7,300 intelligent virtual controllers have been shipped, but as a matter of 'policy' it will not provide guidance on what percent of these use thin provisioning. To date, Wikibon users have reported using thin provisioning of USPV's only in test and development environments, and it appears production instances are more rare. While thin provisioning is not a panacea for all applications, and there are important caveats for users, the feedback from the community is nonetheless positive: Thin provisioning works well for Hitachi and 3PAR customers, and Wikibon members expect Hitachi engineers will get it to work consistently for external arrays.
However, adoption costs are significant. We estimate migration of 100 Tbytes from non-Hitachi 'fat' devices to internal and external thin provisioned volumes will cost $300K (above and beyond normal array hardware and software costs) and require six person-months to implement. Potential benefits are better utilization for all storage attached to the USPV and much simpler storage provisioning and migration. The combination of virtualization and thin provisioning could perhaps increase utilization rates by 35%. That could save the purchase of an entire array. On top of that there are lower commissioning/decommissioning cost, utilities and perhaps administrative costs.
Hitachi also announced the support of high capacity SATA II disk drives for the USPV, a feature of tier 1 storage popularized by EMC. Evidence suggests that demand for these devices is high, with perhaps as much as 25-30% of the USPV customer base planning on taking delivery of these devices in the near term. EMC indicates similarly robust demand for this capability. Despite the higher cost of tier 1 infrastructure, the use case appears to be attractive for low activity archive applications residing within tier 1 environments. On balance, the attractiveness of this approach comes down to the simplicity and effective cost/gb of adding these devices to already installed tier 1 systems.
Action Item: EMC customers should develop a plan that aggressively leverages thin provisioning and storage virtualization where appropriate over the next six to twelve months. They should have that plan on the CXO's desk soon. This will serve to both heighten awareness of the imperative among executives and increase leverage with incumbent suppliers. The possible outcomes of this strategy are: 1) A guarantee from IBM for delivery of similar functionality; 2) Much better terms and conditions on array deals; or, 3) Acceptance of an alternative proposal from Hitachi, Sun or HP.
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