The front runner in very large data centre storage architecture development is probably Google with its cloud computing concept. Sun is probably the only product vendor that has articulated the ideas behind cloud computing with CTO Greg Papadopoulos' red shift analogy.

A signal astronomer's use for helping to define expanding universe ideas is the Doppler effect or red shift; the way light from a star that is receding from us at incredible speed and is a very long distance away already has its light shifted towards the red end of light's spectrum. Some organisations using IT are expanding their IT needs so incredibly fast that Papadopoulos thought that a red shift analogy applied to them.

Google and Amazon, for example, are red shift IT organisations that need to scale out their IT performance, storage and networking capabilities, far, far, beyond anything previously seen or envisaged. Papadopoulos says it is terascale. It is estimated that Google's server estate has passed 500,000 servers. Like Amazon and Microsoft it is building massive data centres around the globe to provide both the capacity - servers, storage, networking - it needs as well as the 24 X 7 access necessary.

But Google does not use a storage area network (SAN). It has no world-wide network-attached storage (NAS) infrastructure. Instead it uses thousands of Linux servers with cheap disks - direct-attached storage (DAS) - and organises their contents inside its own Google File System (GFS). Effectively much storage intelligence has passed from array controllers into the file system.

The huge, explosive ingress of data in red shift IT organisations blows away current storage infrastructures. Google, Amazon, Yahoo! and Microsoft Live need to scale up capacity and storage access performance to unheard of levels to cope with user demand. Traditional SAN and NAS storage architectures cannot cope with the storage demands of multiple petabytes of data and applications needing to capture the constantly incoming flood of data, organise it, provide sub-5 second access, and safeguard its storage.

It's said that the cost/GB of enterprise SAN storage is around $20/GB whereas such cloud computing storage could be as low as $1/GB. You can't get that cost by buying EMC Symmetrix or Clariion arrays, IBM DS8000 DS4000 products or NetApp arrays. You have to buy in commodity disks and organise them using commodity and/or open source software on commodity servers.

SAN and NAS antithesis

Cloud computing storage is the antithesis of traditional SAN and NAS storage. The good news is that relatively few organisations will have the size needed to build out cloud computing infrastructures. The bad news for SAN and NAS storage vendors is that they could be so incredibly massive as to trigger a significant migration of their customers to using storage-as-a-service (SAAS) on the massive clouds provided by Google, Amazon and others.