News International has outlined the pros and cons in its experience using the Amazon cloud, and advised potential users to make sure they architect for failure in software as a service.

The media company, which publishes The Times, The Sun and The Sunday Times, has put 200 of its 1,200 servers on the Amazon cloud so far. While it recognised the benefits of using Amazon's cloud services, News International has also highlighted some of the issues it has experienced with using a public cloud - though it admitted that it was also responsible for some of problems that occurred.

"You get disk corruption once a month. You've got to back up your VMs (virtual machines) in the cloud," Ian McDonald, head of infrastructure and cloud at News International, told the 451 Research Group's HCTS conference in London. He clarified that it was not Amazon disk that get corrupted once a month, but rather that some corruptions were "self-inflicted".

"The thing with Amazon is you can't just pick up a VM and put it on Amazon. You've got to work on the basis that anything can fail."

He added, however, that the good points about Amazon were that it was innovative, cheap and that the company can use it to "spin things up very quickly".

"We are very happy with Amazon overall. The stuff is out there, it works," said McDonald. "But it is a pretty ugly underlying design."

Amazon had not provided comment on its cloud services at the time of writing.

McDonald revealed that while News International could put about 80 percent of its infrastructure into the cloud, it is currently only about 30 percent there.

It uses Google Mail, Google Apps, Salesforce CRM, FinancialForce and last week introduced Salesforce's enterprise social network Chatter across the business. It is in the process of moving from VMware vSphere 4.1 to vSphere 5.

The main constraint to moving to the cloud is that the company did a hardware refresh - including the purchase of new server blades - two years ago.

"We've got some headroom in existing kit. When that comes to end-of-life, I will shift out to the cloud," said McDonald.

News International is moving systems into the cloud on a service-by-service basis, and its editorial systems, which are currently being upgraded, will be some of the last to go into the cloud.

To decide that services are moved, the company has a 'cloud hierarchy', moving from 'do we need this application anymore? To 'can it be delivered as Software-as-a-Service (SaaS), then Platform-as-a-Service (PaaS), then Infrastructure-as-a-Service, to VMware.

"If they say [it must be] physical, we don't do it unless it is absolutely critical," said McDonald.