San Francisco-based Critical Path, which provides Web-based email services for companies such as America Online, US West, and Sprint, said one of its three core mail storage devices failed yesterday morning.
The company would not comment on how many customers or email addresses were left inaccessible. One of the company's clients, Verio.com's TABNet Web hosting subsidiary, has between 15,000 and 20,000 customers, most of which rely on the Critical Path systems, a Verio spokesman said.
According to Critical Path, the outage was sparked by the failure of a Network Appliance mail storage system. All the mailboxes affected were moved to another machine, but the data on the failed machine had to be "cleaned" before service could be restored, a spokeswoman said.
Network Appliance is doing the equipment repair and data recovery work, and the companies hope to have the mailboxes back online by 10 p.m. today, the spokeswoman said.
Critical Path said any email sent to one of the affected addresses is being kept in storage and will be delivered to the unavailable mailboxes as soon as service is restored.
In an apparently unrelated outage, many Netcom ISP subscribers also found themselves without access to email beginning early yesterday.
The company, which was recently acquired by MindSpring, said that one of its mail servers failed, largely affecting customers with last names beginning with "D," according to MindSpring spokesman Ed Hansen.
Other customers also were stuck with slower or temporarily unavailable service as the volume of mail traffic outpaced Netcom's remaining server capacity, he added.
The company said it expects to have service restored by the end of the business day today, Hansen said. Customers with affected mailboxes will likely see a deluge of mail, followed by a slower trickle of backlogged messages as they are re-created from the failed server, he added.