[cisco-voip] What controls how quickly Unity does a MWI resync?

[Robert Kulagowski]

Unity 4.2(1), 72 ports, configured for UM, all ports are configured for 
dialout MWI, port 72 is the only one configured as _only_ MWI.  MWI got 
out of sync last night due to Exchange maintenance, so this morning we 
hit the resync button.

So far, it's been running an hour, and it's still about 20 minutes 
behind "real time".

What factors go into how long it takes Unity to perform a resync?  Is 
there a list maintained by Unity that tells it which lights to turn on 
and off, and it's just slowly making its way through the list?  If 
there's a list, then how can I find out where in the list it currently is?

Or is it hitting each mailbox, checking for new messages, and then 
deciding which ones have new VM?

In the past, it seems like Unity takes a long time and it only uses port 
72 rather than all ports.  Looking at port status monitor shows that the 
server isn't super-busy; the highest utilized port I've seen has been 
port #8.  CPU utilization is low.

However, if we watch long enough, we'll see MWI dialout at about one 
every 5 seconds (for about an hour), and then all of a sudden Unity will 
use 70 ports all at the same time, "catch up", and then it's done.

Why isn't is using all 50-60 ports right from the beginning?