Over time, he says, companies such as SiteMeter will learn to use beta programs, announce changes in advance, run systems in parallel and take other measures when making changes. Meanwhile, let the buyer beware.
Given the much-discussed outages of Amazon S3, Google's Gmail and Apple's MobileMe , it's clear that cloud users need to prepare for service disruptions. For starters, they should demand that service providers notify them of current and even potential outages.
"You don't want to be caught by surprise," says Methvin, who uses both S3 and Gmail. Some vendors have relied on passive notification approaches, such as their own blogs, he says, but they're becoming more proactive.
For example, some vendors are providing a status page where users can monitor problems or subscribe to RSS feeds or cell phone alerts that notify them when there's trouble. "If there's a problem, the cloud service should give you feedback as to what's wrong and how to fix it," Methvin says.
Users should also create contingency plans with outages in mind. At PC Pitstop, for instance, an S3 outage would mean users couldn't purchase products on its site, since it relies on cloud storage for downloads. That's why Methvin created a fallback option. If S3 goes down, products can be downloaded from the company's own servers.
PC Pitstop doesn't have a backup plan for Google Apps, but Methvin reasons that with all of its resources, Google would be able to get a system such as e-mail up and running more quickly than his own staffers could if they had to manage a complex system like Microsoft Exchange. "You lose a little bit of control, but it's not necessarily the kind of control you want to have," he says.
Overall, it's important to understand your vendor's fail-over strategy and develop one for yourself. For instance, Palo Alto Software offers a cloud-based e-mail system that uses a caching strategy to enable continuous use during an outage. Called Email Center Pro, the system relies on S3 for primary storage, but it's designed so that if S3 goes down, users can still view locally cached copies of recent e-mails.
Forrester Research advises customers to ask whether the cloud service provider has geographically dispersed redundancy built into its architecture and how long it would take to get service running on backup. Others advise prospective users to discuss service-level agreements with vendors and arrange for outage compensation.