Tag Archives: exchange

What happened last week?

I picked a good week to go on vacation.

VoIP users–specifically, Unity voicemail subscribers–at Penn State received e-mail notices from Saturday the 18th through Tuesday the 21st that voicemail services were unavailable. Here’s some more technical information as to what happened.

Unity uses Microsoft Exchange as its back-end message store. PSU’s configuration of Unity is voice-mail-only (VMO), meaning that the Exchange part of the system is completely hidden from and inaccessible to the user. (A more popular configuration of Cisco Unity is unified messaging (UM), where Unity is integrated with a company’s Exchange mail system; users see both e-mail and voicemail (as attached sound files) in their Outlook inbox, and can also manipulate both voicemail and e-mail through the telephone interface.) When the Exchange message store goes offline, callers can still leave voicemail, but it doesn’t get delivered to a subscriber’s voicemail box until Exchange is up and running again. Last weekend, one of the two Exchange servers that serve Unity experienced a full mailstore disk, leading to some corruption of the Exchange database which, I’m told, took a while to repair. Subscribers whose boxes were on that particular server wouldn’t have had access to them during the repair time. But one of the great features of Unity is that it stored those new incoming messages until that Exchange server was back up, at which time all the new messages were delivered. No messages were lost.