The technology is called thin provisioning, and is part of an update to the company’s flagship TagmaStore disk array.
Hitachi’s storage subsidiary Hitachi Data Systems is keeping details of the update to the under wraps until today. But its OEM customer Hewlett-Packard briefed journalists about the new gear last week, under news blackout agreement until this morning. HP will begin shipping its version of the box, which it has christened the HP XP24000, in July.
On the hardware side, the update gives the jumbo storage device even more storage capacity and data pumping power. Out goes 2GFC, and in comes 4GFC from back to front, increasing throughput up to four-fold, according to HP. HP also said that it has reworked its prices to make smaller XP configurations cheaper. A 1TB configuration will carry a list price of $260,000, less than for the XP12000 device that is being superseded by the new gear.
Like their major rivals EMC’s DMX and IBM’s DS8000 disk arrays – the TagmaStore and its XP24000 variant were already more than powerful enough for the huge majority of customers, and the re-work simply provides yet more headroom and scalability for these buyers.
But the appearance of thin provisioning in the TagmaStore and XP24000’s virtualization software will appeal to a wide range of customers.
Thin provisioning allows customers to allocate more storage space to applications than is physically available. This counteracts the effects of the very common practice of over-provisioning capacity to applications in order to provide room for data growth, and can hugely increases disk utilization rates.
Among the very few storage suppliers of thin provisioning at present are 3PARdata, Network Appliance, LeftHand Networks and DataCore Software. EqualLogic is set to join the club this week, and Pillar Data Systems says it will pile in during the third quarter. EMC and IBM will make no comment about when they will ship thin provisioning.
3PAR was first to market with thin provisioning in 2003, and the technology has been one of the major reasons why the privately-held company has managed to carve itself a space in the highly competitive high-end storage market.
Disk utilization rates vary from data center to center, and analysts frequently quote 50% as a typical percentage. But 3PAR customers in the commercial sector say they are achieving utilization rates exceeding 90%, while service providers using 3PAR’s gear claim utilization rates of 150%. For every 30TB of space that these service providers allocate to customers, only 20TB is physically present.
That results in better usage of expensive high-end storage capacity, and on a per-TB basis it also slashes power consumption and heat generation. As a result 3PAR has been pitching thin provisioning as a green technology, and Hitachi and HP are very likely to follow suit.
One criticism of thin provisioning is that if it used wrongly, it can increase the risk that an application will crash because it has run out of storage space.
That’s the real challenge of any provisioning technologies. If you have applications with runaway data growth, you can get into trouble, said HP’s product director Kyle Fitze. The HP XP24000 will issue alerts to administrators warning that applications are approaching their capacity limit. That’s critical, said Fitze.
Other issues involved with thin provisioning are performance and the ability of replication tools to work with thin provisioning at both source and target.
On the performance front, HP said that the XP24000 with thin provisioning is typically as least as good as the XP12000 box that it supersedes, although it warns that a user not following array configuration guidelines could end up with performance that is not satisfactory.
While local, in-box replication can be made between thin provisioned data volumes, the software does not yet support remote or box-to-box replication with thin provisioned volumes on both sides.
