Unisys is offering pay-for-use storage, based on real-time storage (RST) usage metering. Customers have EMC or HDS arrays installed and pay for their expected use per month. If they use less they pay less and if they use more they pay more.

The storage can be configured in the way a customer wishes: direct-attach; network-attach; or storage area network. Unisys models the customer's storage usage and its trend and then installs enough terabytes of capacity to meet the expected need over a three or four year term.

A monthly payment is set based on the expected usage measured over the term in GB/month units - how many GB are needed per month. Customers buy the right to use the expected number of GB/month units during the term. The daily storage consumption is measured (GB/day units) and this is summed up to provide the actual monthly usage figure. If it is less than expected the customer's bill is reduced pro-rata. Similarly it goes up if usage is higher.

However, if not all the GB/months have been used at the end of the term the customer can have a three months' extension in which to use them up at which point any further unused GB/months are lost.

Steve Rawsthorn, Unisys' EMEA VP for systems and technology, says this is a cheaper way of paying for storage over a 4-year period than buying it outright. It is, he said, less than a capital purchase even after factoring in a 25 percent per annum price erosion. He also said that customers have all the storage they need over a three or four year term installed at once. They don't have to suffer outages for later capacity upgrades, or restrictions in their capacity needs until an upgrade is installed.

Naturally if the customer has an unanticipated jump in capacity need, greater than the TB of storage in place, then this may not be true.

The customers do not own the storage and its cost can be treated as an expense instead of a capital outlay. Unisys has offered leasing terms for its IT products for some time and this can be seen as a variation on that.

Two financial institutions in The Netherlands are already using this RTS payment method for EMC Symmetrix arrays. Eric Shefler, an EMC EMEA VP said: “Unisys customers can benefit from a powerful combination of incremental scalability, constant availability and exceptional data mobility achieved through the Real-Time Storage metering solution.”

Pay-for-use is a utility or grid computing idea. Sun has a grid storage offering costing $1/GB per month. It is accessed over a network link, the cost of which has to be factored into the equation.

HP is working on a storage grid. IBM is developing grid-style storage at CERN and has a lot of grid storage technology work going on. It appears that Sun and Unisys are way out in front in terms of having an actual utility storage offering.