Over the past several years, some organizations have done just that, consolidating and virtualizing x86 servers using Linux on the mainframe. Once you start doing that, you have the basis for a private cloud.
"You have this incredibly scalable server that's very strong in transaction management," says Judith Hurwitz, president and CEO of Hurwitz & Associates, an IT consultancy in Needham, Mass. "Here's this platform that has scalability and partitioning built in at its core."
Plus, the mainframe's strongest assets -- reliability, availability, manageability and security -- are the very characteristics that companies are most concerned about as they consider rolling out major business applications in the cloud, she says.
The Sticking Point: Provisioning
But that lack of support for self-provisioning is glaring. "The mainframe is very well controlled in most organizations, often to the point where it's locked in a room and people can't access it," says Julie Craig, an analyst at Enterprise Management Associates. "[Mainframe vendors] are going to have to do some developing to allow the self-service features of the cloud."
Reed Mullen, IBM's System z cloud computing leader, says that the lack of self-provisioning is cultural, not technological. Companies could enable self-provisioning in mainframes either by using IBM's Tivoli Service Automation Manager or through custom development, he says.
The five characteristics of a private cloud:
1. Scalable: High levels of utilization (e.g., through virtualization), with large, mature data centers.
2. Accessible: Users can provision resources on their own.
3. Elastic: Appearance of infinite capacity on demand.
4. Shared: Workloads are multiplexed; capacity is pooled.
5. Metered consumption: Ability to pay for use with no commitment.
Source: Corporate Executive Board's Infrastructure Executive Council, Arlington, Va.
And yet he acknowledges that such implementations would still depend on the IT department -- users wouldn't have full self-service autonomy. Specifically, mainframe systems with self-provisioning options would require a user to submit a request by email, and IT would have to approve the request before the resources were provisioned, Mullen explains. This reflects the "old habits" of the mainframe world, he says. But he also notes that any kind of cloud implementation, including those on distributed systems, would include an approval process.