Hitachi isn't the first vendor to offer unified block and file storage in one package. One competing example is EMC's VNX product line, which offers unified storage and a suite of virtualization features. In particular, the VNX7500 feature set tracks closely to the HUS VM. It offers similar storage virtualization features, including thin provisioning, snapshots and replication; it can mix and match spinning and SSD drives; and it falls just shy of HUS VM's raw internal capacity, at 2.9 Pbytes. This June, Dell Compellent announced the SC8000 controllers, which also unify block and file storage.
Hitachi says the new product is aimed at "entry enterprise" customers, such as regional health centers or universities. HUS VM "fills a significant gap between HDS's lower-end systems and the Virtual Storage Platform at the high end," says Henry Baltazar, a senior analyst at 451 Research. He notes that while the new product offers only a marginal improvement in capacity over HDS's midrange HUS 150 (3.4 Pbytes, up from 2.8 Pbytes), its 256-Gbyte cache is eight times the size. It also offers twice as many Fibre Channel ports (32 versus 16).
The product's storage virtualization features aren't groundbreaking, but they do enable useful capabilities such as synchronous replication between HUS VM products. Synchronous replication ensures that data is copied in real time to a physically separate storage system, which is critical for disaster recovery and business continuity of transactional systems. Replication is the most important storage technology for IT, according to the InformationWeek 2012 State of Storage survey . Respondents rated snapshots as the third-most-important technology; the HUS VM also offers this feature (which Hitachi calls internal replication).
Hitachi also touts the product's ability to perform tiering, which moves frequently accessed data to high-performance disk. However, our survey shows that tiering isn't a priority for respondents; this feature came in 12th out of a list of 15 options.
In addition to storage virtualization features for disks within the HUS VM, the product can also virtualize external, third-party storage. The company says it supports more than 100 models, or any system that's compliant with the SCSI-3 standard. While the virtualization of external storage can increase HUS VM's overall capacity, the product may not be able to support advanced features provided in the external storage systems.
HUS VM includes two controllers for block storage, which the company says behave like a single device. The controllers are connected with an internal crossbar switch and share cache and resources, so that if one controller fails the other can take over immediately. The company also says the controllers' microcode and hardware components can be serviced while in operation. For file storage, the product includes an object-based file system and uses custom FPGAs. As for disk options, it can support a maximum of 1,152 SAS or SSD drives.
"Hitachi announced earlier this year that it was bringing its own flash controllers to market, which could give HDS storage products such as the HUS VM a performance boost in the future with the addition of solid state storage," says Baltazar.
Hitachi offers separate software packages for different features. The base OS includes thin provisioning (which Hitachi calls dynamic provisioning). Other features, such as tiering and replication, must be licensed separately. Pricing starts at $156,000 without disk capacity, though it does include the base OS package and maintenance.