We set up a new domain and moved our users to mailboxes on a new Exchange 2010 organization several months ago. We have not been using the calendar features of Exchange until about a month ago.
Outlook 2003 users are now seeing delays when opening the scheduling tab of a calendar item with multiple attendees, so that the free-busy information for each of those users is displayed. Each user will show up with a grey bar, and take a long time
(usually around 45 seconds per user) to update to the blue bands showing free and busy times. Obviously when displaying 10 or 20 users or more, this is taking an extremely long time to complete.
We also have Outlook 2010 users, and they are not having this problem at all. Free-busy information displays nearly immediately for large numbers of users. We haven't checked with Outlook 2007 since we are not generally using it, but I expect that since
it doesn't use public-folder based Free-busy publishing, it should also have no issue.
We have four Outlook 2010 SP1-RU6 mailbox servers, with public folder databases on two of those servers. The Schedule+ Free Busy system folders are replicated to both servers and both have the same number of items in the folders (a bit over 15,000 items).
I took a look with the MDBVU32 tool at the contents of the folders and found items for each of the users I was looking at, so the folders appear to be correctly populated.
First, is 45 seconds per user an unusually long time to display the free-busy data? It seems so to me, but since we had not been using calendar data before I don't have a baseline to compare against.
I am assuming that this is some sort of issue with retrieving this data from the public folder. Users have suggested that these lookups were originally faster but have been getting slower recently. Lookups also seem to run faster during off-hours when less
users are accessing the mailbox servers. Is this likely to be a performance issue with the mailbox & public folder servers?
If anyone has suggestions for how to further investigate this issue, or have seen similar behavior in your environments, I would appreciate your suggestions.
Regards, James