The new HDS Storage Reclamation Service (SRS) can provide a quick sampling of a handful of a customer's hosts and their attached storage at no charge, or customers can choose a more comprehensive assessment of how much storage can be freed up in the environment by using Hitachi Dynamic Provisioning (HDP) software.
Before undergoing a comprehensive assessment, the customer and HDS service engineers would agree on how much storage would need to be reclaimed for the rest of the thin provisioning process to be worth the cost of the software. If Hitachi Data Systems can identify that amount of unutilized storage in the environment, the customer would pay for the assessment. If not, the assessment would be free. The customer would then pay HDS for services to help deploy HDP and realize those savings.
Hitachi Dynamic Provisioning software creates virtualized disk pools that can be overallocated to provide thin provisioning and can also wide-stripe data across all of the drives in the disk pool for performance improvement through parallelization.
With today's software update, the load-balancing feature will automatically restripe data across any new capacity added to the pool. The software will also automatically return unused storage capacity to the dynamic provisioning pool, a feature HDS is calling Zero Page Reclaim. Hitachi Dynamic Provisioning also supports Hitachi's Adaptable Modular Storage 2000 (AMS 2000) midrange disk arrays with this release, but will not offer Zero Page Reclaim for the AMS 2000.
Neither of these capabilities is new to the storage world. For years, storage arrays from Dell Inc./EqualLogic and Hewlett-Packard (HP) Co./LeftHand Networks have been able to restripe data across all drives in a system when new capacity is added. The ability to automatically return unused capacity to the dynamic provisioning pool has also been available from vendors such as 3PAR Inc. and Compellent Technologies Inc.
John Harker, senior product marketing manager at Hitachi Data Systems, said HDS considers its approach unique. "What most people do over time is 'passively' use new drives as new data is added, but this automatically does active rebalancing," he said. "Each virtual volume is also rebalanced in addition to the physical capacity."
Rodney Willms, senior storage engineer at Sacramento, Calif.-based Sutter Health, said he upgraded two disk arrays to Hitachi's Universal Storage Platform V (USP V) with Hitachi Dynamic Provisioning last year to take advantage of dynamic load balancing. Prior HDS models could concatenate drives across two RAID groups. Hitachi Dynamic Provisioning allows pooling of the capacity of an entire array, whether or not a customer actually overallocates storage for full-blown thin provisioning. "Our struggle was performance," Willms said. "We were the first people to deploy 100% HDP pools."
However, Willms has yet to embrace thin provisioning by overallocating logical unit numbers (LUNs). "If you just don't overallocate, you really don't cross the line into thin provisioning," he said. Willms said he worries that if he reached 100% capacity on an overallocated pool, he wouldn't be able to get new capacity configured in time to avoid running out of data storage space.
However, Willms said he's reconsidering deploying thin provisioning because of financial belt tightening. "As you can expect, with the downturn of the economy, Sutter Health is trying to do more with less. We can clearly see the benefit of 'cost avoidance [from implementing thin provisioning].'" However, he said wouldn't use the assessment service if he does decide to go that route. "It's pretty easy for us to do that in-house," he said.
Willms said he hopes the next Hitachi Data Systems update improves integration between its Device Manager and Tuning Manager. Device Manager will show all of the storage assigned to hosts in the environment through a Java GUI, but there's no way for him to export that information to Tuning Manager to act on it.