This week Hitachi launched their entry into the Unified storage array marketplace (press release). Hitachi Unified Storage (or HUS) as it will be known, takes AMS2xxx arrays and BlueArc NAS gateway/heads, combining them together to produce a unified platform. We’ll come back to Hitachi in a later post, but in the meantime, I think it is worth questioning whether Unified is a genuine category or not.
The word “unified” in Unified Storage is meant to mean a unification of the common access protocols; block and file. Typically, many arrays cover only a subset of available storage access methods – CIFS/NFS, iSCSI and/or Fibre Channel. However, take a look “under the hood” and you will see that many of these products – from a physical perspective – are not unified at all. EMC’s VNX is a marketing triumph, bringing the CLARiiON and unloved Celerra platforms together into what is sold as a magical single product. In truth it’s far from that, with the two separate products still existing in physically separate shelves, albeit with a shiny new bezel. Having a single management interface, of course does help to complete the illusion.
Probably the only big vendor selling a true unified platform is Netapp. They have pretty much always offered the standard range of protocols, including iSCSI at no extra cost. However, even this platform isn’t a perfect solution; in previous years I’ve done performance and capacity comparisions of Netapp versus the competition for block storage and found it significantly lacking in horsepower, something I know they’ve worked on in recent years.
Should we care if the hardware isn’t fully integrated? Does it matter that we’re putting components together like a 1970’s hi-fi system? Well, like everything, it depends. Building a hi-fi system out of individual components is pretty straightforward; the standards and links between each piece are well defined and consistent. Pulling together NAS gateways and storage from different vendors is fraught with support issues and taking a single “unified” product guarantees support is from a “single throat to choke”, even if each piece isn’t best of breed. It also means simplified management too.
Unified storage products are great for smaller organisations, especially those without dedicated storage teams. However where performance and scale are important, unified arrays are probably not the optimum solution. As with everything in IT, there’s no right or wrong way, just many shades of grey.