Hey Donkey, I produce Entourage (And brought Exchange to a screeching halt!)

No, I’m actually not talking about the crazy SNL skit and follow-up with Mark Walhberg!

No, I’m talking about Exchange and its IO going through the roof when you use Entourage for the Mac in a typical Exchange environment.

Microsoft has a KB329067 Article which relates to this issue with some ‘guidance’ on how to correct it, but exactly how far you take it is another matter.

Information about performance issues that occur when you use POP3, IMAP, or WebDAV clients, such as Entourage, after you move mailboxes in Exchange Server 2003 or in Exchange 2000 Server

Basically, what you’ll get from this article is this:

1. Start Registry Editor.

2. Locate and then click the following registry key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeWEB\DAV

Note By default, the DAV key is not in the registry. You will have to create it yourself.

3. On the Edit menu, click Add Value, and then add the following registry value:

Value name: MaximumResponseSizeInBytes
Data type: REG_DWORD
Radix: Decimal
Value data: value

For example, if you decide to increase this value to 500 megabytes (MB), use the following calculation:

1024 * 1024 * 500 = 524288000 (Decimal) = 1F400000 (Hexadecimal)

Enter the results of this calculation in the Value data field. In this example, you would enter 524288000 (Decimal) or1F400000 (Hexadecimal). Remember that the configurable range for this registry key is 1 MB to 1 gigabyte (GB). Better results occur if customers set it to a value of 500 MB or a higher value, such as 800 MB.
NoteWe recommend that you set the value back to the default value or to a lower value after the content conversion issue subsides in your organization. The default value of this registry key is 128 MB. We also recommend that you set correct messages limits and mailbox size limits on your Exchange server to prevent performance issues.

4. Exit Registry Editor.

I can only read this particular KB article so much before I say “Hmm, but what actually works?”

Here is a solution which is tried, true, and used and tends to work most of the time.

Modify this Key to this value:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeWEB\DAV

Value name: MaximumResponseSizeInBytes

Decimal: 838860800

What this does is set it to 800MB, as opposed to the ‘referenced’ 500MB example.

In a majority of all circumstances this will take considerable strain off of both your Exchange server as well as your underlying storage.   The end result is, Marky Mark and the Entourage Bunch won’t cause Exchange to Spike and cause severe latency issues for your users.

I think that calls for a definite win situation!

Kind of like how Andy wins in this situation…!