With 24.1% of the overall market, according to research firm IDC, Amazon is the world's biggest cloud computing firm. Rivals like Microsoft Corp, Alphabet's Google Inc and Oracle Corp are trying to lure AWS customers to use parts of their clouds, often as a backup.

But crafting a complex online service that can be easily shifted from one provider to another in case of emergency is far from simple, said Naveen Chhabra, a senior analyst with research firm Forrester. Rather than being a singular "cloud," AWS is actually composed of hundreds of different services, from basic building blocks like computing power and storage to advanced services like high-speed databases and artificial intelligence training.

Any given website, Chhabra said, might use several dozen of those individual services, each of which must work for the site to function. It is difficult to make a backup on another cloud provider because some services are proprietary to AWS and some work very differently at another provider.

"It's like saying, 'Can I put an SUV body on a sedan chassis?' Maybe, if everything is all the same and lines up. But there is no guarantee," Chhabra said.

Another issue that makes it hard for businesses to diversify is that AWS makes it relatively cheap to send data into its cloud, but then charges higher prices for "egress fees" to get data out of its cloud to take to a rival.

"That amplifies issues like this (outage) when they happen," said Matthew Prince, chief executive of internet security firm Cloudflare Inc, "A more resilient cloud is one where egress fees are eliminated and customers can be multi-cloud. I think that would actually increase the faith customers have in the cloud."...

Source: https://www.reuters.com