Some forums have started to register problems with excessive growth of transaction logs for databases hosting the mailboxes of iOS devices that have been upgraded to iOS 6.1 Another interesting report indicating that some form of synchronization loop can happen was posted to the forum used by folks who support the F5 load balancers that are often used to front-end large Microsoft Exchange Server deployments.
iOS 6.1 devices are hammering Exchange servers with excessive traffic, causing performance slowdowns that led Microsoft to suggest a drastic fix for the most severe cases: throttle traffic from iOS 6.1 users or block them completely.
"When a user syncs a mailbox by using an iOS 6.1-based device, Microsoft Exchange Server 2010 Client Access server (CAS) and Mailbox (MBX) server resources are consumed, log growth becomes excessive, memory and CPU use may increase significantly, and server performance is affected,"
Microsoft suggests several fixes, starting out gently, and then escalating to the complete blockage of iOS 6.1 devices. Based on the fixes suggested, the problems may be caused when iOS devices connect to Exchange calendars.
The first workaround is "do not process Calendar items such as meeting requests on iOS 6.1 devices. Also, immediately restart the iOS 6.1 device."
If that doesn't work, users are instructed to remove their Exchange accounts from their phones or tablets while the Exchange Server administrator runs a "remove device" command on the server side. After 30 minutes, users can add the Exchange accounts back onto their devices but should be advised "not to process Calendar items on the device."
Microsoft's techno offers three workarounds for the bug:
- Remove the Exchange account from the device
- Create a custom throttling policy for iOS 6.1 users
- Block iOS 6.1 users