Exchange: Blackberry + Large MBs = Recipe for Latency
Blackberry is a very resource intensive application and is known to be a very "chatty" application. I've heard BES (Blackberry Enterprise Server) is known to produce 5-6 times as much MAPI traffic as an average client, but never came across any documentation as to how this was figure was formulated. However, I have seen BES in conjunction with large mailboxes (1GB+) cause an exponential affect as far as performance degradation. Take the following case scenario below.
In this scenario, users were reporting "Outlook is requesting data" pop ups frequently. This would occur for BES users as well as non BES users. Now to give you the specifics of the hardware platform:
Proliant BL20P G2 (Backended to a SAN)
2 Quad Proc 2Ghz
Windows 2003 Ent
Exchange 2003 Ent
This server hosted approximately 350 users and was originally sized to support 3,000 users. However, users were already complaining about Outlook latency.
Exchange Performance Analyzer, reported high RPC activity which was the source of the latency. No other bottlenecks were reported. We investigated disk I\O, memory, CPU and everything reported normal.
We consulted with our Microsoft ASE. The culprit was our BES users in which this server hosted approximately 186 with about half of them having mailboxes at 1GB and over. However, the size of the mailbox is not what causes the latency but specifically the number of items in your Outlook folders. This is because the more items you have, the more likelyhood that these items are stored in mutiple tables and pages within the database. Therefore, Exchange has to traverse this tree in order to link and process operations such as categorized views. Now large mailboxes in conjunction with BES, which is a very resource intensive application was a perfect "RECIPE FOR LATENCY" I've also seen desktop search engines also cause a similar affect in which 20 users running Google Desktop Search Engine caused the Exchange Store.exe process jump from a 2%cpu baseline to 17%cpu baseline.
What we ended up doing was to export the item count for all users on this server user PFDavadmin, (I have a blog on this referenced at bottom) and then filtered for users who had more than 10000 items. (Choose the figure that you want to work with) We then had users clean out their mailboxes.
Outlook users experience poor performance when they work with a folder that contains many items on a server that is running Exchange Server 2003 or Exchange 2000 Server
Exchange: Exporting Mailbox Properties Using PfdavAdmin
Microsoft Exchange Analyzers
Exchange 2000 Server and Exchange Server 2003 performance may be affected when desktop search engine software is running on Outlook or other MAPI client computers
MCSE M+, S+, MCTS, Security+
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