Exhange server preprocesses outlook attachments before sending email

[grootnet]

Hello

Yesterday the transaction partition (20GB) of our Exchange 2003SP1 filled up within 90min. The database grew 12Gbytes. The newly acquired data is no-where to be
found not in the mailboxes or public folders. After running eseutil /ms and isinteg -dump I found-out that the "MDB Attachments Folder" contains the
data. The sum of the mailboxes should be equal or larger then the database file size. In our case the database file is 12GBytes larger. It looks like a mapi client (outlook)
stuffed the database with 12Gbytes of attachments without pointers/links towards a mailbox.

I could replicate the problem by starting Outlook and adding a very large attachment (400MB) to a new message. Before sending the message the tranaction logs grew +/- 500MB. What is the deal with Exchange adding
attachments to the mail store before they are being send / or being refused to send because of delivery restrictions? If you decided not too send the message it’s still allocated in the database but without any links/pointers
to a user mailbox. Is this by design? If so, why?

Try this in your test enviroment:
Start Outlook > Create new mail | Add attachment (+ 200MB)
Stop here; logon to your Exchange server and watch the trans-logs and database file grow. When it stops adding trans-logs cancel the new mail. Your database has just grown 200MB now check your mailbox resources in
"Exchange Manager". You will not see the 200MB attachment in your mailbox resources.

Thanks,

 

[xmsre]

Content conversion from MAPI to MIME, that's the deal. Content conversion takes place in the working directory as defined by the server attribute MSExchDataPath. If there is an error in the conversion process, you can end up with the attachment added to the attachment table and the message is not sent. A couple of days later the user gets an NDR.

There's a fix for that.

http://support.microsoft.com/default.aspx?scid=kb;en-us;823494