Defining Unified

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.

Market Positioning

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.

1. A piece of hardware that has CPU, Memory and disk
2. That supports FC, iSCSI, CIFS and NFS
3. That has a common management console for all storage functions that are not protocol specific
4. Has a single replication mechanism that is independent of protocol

Quite how and why this narrow definition should define something that is classed as unified, I’m not sure, however if you watch the video you’ll see it’s a direct attack at Netapp’s arch nemesis, EMC.  Does this mean Unified Storage is a real concept or just an attempt to have a dig at the competition?

Here’s a few thoughts:

1. How many (persistent) storage devices do you know that don’t contain CPU, memory and disk?
2. What have FICON, ESCON, Infiniband, SCSI, AoE and FCoE (and others) done to deserve exclusion from the term “Unified”?
3. Why permit exclusions from a common management console?  Surely common means it does everything?  Otherwise it’s not common.
4. Why is  a single replication mechanism so superior?  Isn’t choice a good thing?

There are other storage vendors out there.  Some of them even use the Unified moniker too – with just cause.  So here’s my more generic definition of Unified Storage:

1. A hardware device dedicated to data storage.
2. A device which supports all commonly used protocols, including Mainframe and Open Systems standards.
3. A device which enables *all* configuration to be performed through a single management interface (regardless of whether multiple interfaces are supported)
4. A device which provides consistent performance/throughput, regardless of the protocol used.
5. A device which scales.

Now does that actually exist?