Hitachi Data Systems' USP-V high-end disk array will now be able to thin-provision volumes on competitors' disk...
arrays which are attached to its storage virtualization controller as external storage.
The new feature, which users can access by purchasing a software license key, works the same way that Hitachi Data Systems' (HDS) heterogenous virtualization works with third-party systems, according to HDS chief scientist Claus Mikkelsen. To external storage systems, the HDS controller looks like a Windows host, and as such, is allowed to provision and control LUNs on the array. Since this also means that HDS has not had to use APIs from competitors to create the feature, it will work with any third-party system the USP-V can already virtualize, including EMC's entire Symmetrix and Clariion lines, IBM's Shark and DS series arrays and Hewlett-Packard's (HP) EVAs.
"This completes the picture of what most customers want to see with storage virtualization," said Tom Trainer, analyst with the Evaluator Group.
But storage virtualization continues to evolve. Today 3PAR is launching virtual machine software that carves virtual partitions within its InServ Storage Server arrays.
Thin provisioning and RAID not yet combined
And thin provisioning is still evolving for HDS. The feature still isn't supported as a replication source or target, though users can work around that by taking snaps of thin-provisioned volumes through ShadowImage and replicating those. "We are holding back on combining thin provisioning [with things like replication #93; for the same reason we held off on external storage thin provisioning in the first release," Mikkelsen said. "We want to stay on the safe side." Thin provisioning is supported on RAID 6 volumes, according to HDS officials.
Some of HDS' users are similarly conservative. "We just cut over entirely to our new array," said Ed Kosten, supervisor of Unix systems engineering for Priority Health and an early adopter of USP-V. The company is testing thin provisioning as a means to save money on high-end internal storage, but Kosten said he wasn't sure if external storage thin provisioning would pass a cost-benefit analysis at his shop.
"It's hard to imagine the benefit of adding external storage and thin provisioning licenses to cheap disk," he said. "It will give me some ROI on high-end disk, but in our environment, I don't know if it would actually save me anything when it comes to our external storage arrays."
Keeping an eye on startups
While HDS, EMC and IBM are the main vendors of high-end storage arrays, the inclusion of features such as thin provisioning and MAID, which HDS recently added and EMC said it will soon offer, shows that these vendors are keeping an eye on what startups are doing. 3PAR has been making forays in the high end by emphasizing management simplicity over legacy products. HDS has streamlined pricing on its licenses recently, but more consolidation is needed, experts say.
"The 3PARs of the world can tell you that HDS is really complicated, and their product isn't, and that's true," said Enterprise Strategy Group (ESG) senior analyst Tony Asaro.
3PAR hopes to stay ahead in the virtualization game with its Virtual Domains that let users carve up partitions within arrays, each with its own set of policies and permissions. 3PAR marketing vice president Craig Nunes likens it to the storage equivalent of virtual machines on servers.
"A Virtual Domain is like a VMware virtual host," he said. "Virtual domains do for storage what hypervisors do for servers," he said. "On the server side, they've evolved with simple dynamic provision of virtual machines. That's where this brings us on the storage side."
Other high-end storage systems allow similar virtualization. IBM brought LPARs from its mainframes to the DS8000 and HDS offers Virtual Partition Manager to set up partitions inside arrays. Analyst Steve Norall of the Taneja Group said that 3PAR's approach is different because it does not limit utilization. "With LPARs, you carve up a box and say, 'This amount of CPU, cache and disk are a partition,'" he said. "It's a physical partition. 3PAR provides a virtual array inside a physical array. The data is striped across the array, and all the controllers are leveraged."
Pricing for Virtual Domains begins at $1,500 and varies based on InServ configuration. Virtual Domains for an InServ with more than 100 drives and tens of terabytes configured could cost as much as $20,000.
(News Director Dave Raffo contributed to this story).