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 For example, this note describes a situation where upgraded devices seemed to go into a loop and ended up by generating some 50 GB of transaction logs.
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.
I’ve picked up a few other reports that cannot be publicly attributed at this point that also refer to excessive transaction log generation after iOS 6.1 devices are introduced into Exchange 2010 or Exchange 2007 environments. I assume the same is true for Exchange 2013 as the underlying cause is likely to be in Apple’s mail app code that calls ActiveSync to synchronize with a user’s Exchange mailbox, with some indications being that the problem is once again associated with calendar events. You’d think that Apple would have learned after the iOS 6.0 calendar hijack fiasco.
In any case, for now the best idea is to tell users not to upgrade to iOS 6.1 until the situation becomes clearer. Consider implementing an ActiveSync device access rule to block iOS 6.1 clients connecting if people won’t listen to the advice not to upgrade. It just doesn’t make sense to allow some rogue devices to wreak havoc on your infrastructure.
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