Gmail malfunctioned on Monday, affecting individual users as well as those for whom this service is their primary workplace e-mail tool via the Google Apps hosted software suite.

It's the second Gmail outage in less than a week, and as the service wobbles, questions persist about Google's ability to provide enterprise-grade software availability and performance.

Google is heavily promoting its Apps collaboration and communication software suite as a SaaS (software-as-a-service) option to conventional, on-premise options like Microsoft's Office and Outlook/Exchange.

While so-called cloud computing services like Apps, in which software and IT infrastructure are provided via the Internet, are convenient in several ways, their Achilles heel is server downtime and slowness.

With suites like Google Apps, vendors host the software in their own data centers, freeing IT and business administrators from the hassles of installing and maintaining applications and from the costs of provisioning hardware for them.

However, when applications go down at the vendors' data centers, IT and business administrators can only fret and wait for the issues to be fixed, leaving them helpless while their end-users complain.

A sampling of how frantic IT and business administrators can get when their vendor-hosted software goes offline can be found in this thread at the official Google Apps Discussion Group devoted to Monday's two-hour Gmail outage.

"Need resolution immediately! I dumped Exchange for Google Apps, please don't disappoint me," reads one message.

Another flustered Apps administrator wrote: "Me too, need a fix fast. I have 20 people calling me wondering why this is down. I think they're going for the rope. Please hurry!!"

Yet another wrote about possibly giving up Apps: "Not at all happy, this is the second time in two weeks this has happened and I see it has happened a number of times in the past. Last time it took 18 hours to fix, not acceptable."

Google didn't immediately reply to a request for comment, so the scope of the problem is unclear, but it apparently was significant enough to warrant a rare apology on the official Gmail blog.

"Many of you had trouble accessing Gmail for a couple of hours this afternoon, and we're really sorry. The issue was caused by a temporary outage in our contacts system that was preventing Gmail from loading properly," wrote Todd Jackson, a Gmail product manager.

The IDG News Service is a Network World affiliate.