struggled Friday to restore computers used by other major websites such as Reddit as an outage stretched beyond 24 hours.


The problems began at an Amazon data center near Dulles Airport outside Washington early Thursday. On Friday morning, Amazon's status page said the recovery effort was making progress, but it couldn't say when all affected computers would be restored.

Most of the sites that were brought down by the outage on Thursday were back up on Friday, but news-sharing site Reddit was still in "emergency read-only mode," and smaller sites were still reporting trouble.


'It's a pretty vulnerable feeling. This is a really big message to us that we need to revisit our strategy '—Josh Cochrane, Palo Alto Software

Location-sharing social network Foursquare and HootSuite, which lets users monitor Twitter and other social networks more easily, appeared to have recovered.

Many other companies that use Amazon Web Services, like Netflix Inc. and Zynga Inc., which runs Facebook games, were unscathed by the outage. Amazon has at least one other major U.S. data center that stayed up, in California.

It's not uncommon for internet services to become inaccessible due to technical problems, sometimes for hours or even days. But the outage is notable because Amazon's servers are so commonly used, meaning many sites went down at once.

Amazon, which had not responded to requests for comment, has not revealed how many companies use its internet services or how many were affected by the outage.







But cloud computing isn't immune to failure, either.

Backup system appears to have failed





But the firm's websites and web-based applications that create business plans were all brought down by Thursday's crash.




Amazon shares rose $2.02 US, or 1.1 percent, to close Thursday at $185.89.