Microsoft KB Archive/118359

= Mac Srv: Mail Data Files Can Increase in Size Quickly =

Article ID: 118359

Article Last Modified on 10/30/2006

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APPLIES TO


 * Microsoft Mail for Appletalk Networks 3.0
 * Microsoft Mail for Appletalk Networks 3.1

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This article was previously published under Q118359



SUMMARY
In versions 3.0 and 3.1 of Microsoft Mail for ApleTalk Networks, the Mail Data file can grow large quickly in some known cases. Many of Mail's operations or algorithms use a lot of disk space, to be reclaimed during compression in the interest of making the Mail server faster.



MORE INFORMATION
Sending an enclosure to a user on another server is expected to temporarily increase the destination server's data file by twice the size of the enclosure. This is because a server to server "wrapper" containing the enclosure and the message is sent across the network, which the destination server then must unpack into its parts: the enclosure and the message.

The original wrapper is then "deleted," but its space in the data file may not be reclaimed until the server has been relatively idle for a while (for example, overnight). This unreclaimed space may actually be used by the server before the compression routines kick in. In some cases (for example, an active server with lots of free space in its data file), an incoming message or enclosure may actually not increase the size of the data file at all; free space within the data file (of the right size) can be used for the wrapper and its parts.

Breaking up this wrapper is called "message delivery." This is where all recipients of the message get a copy in their mailboxes. Mail does not duplicate the message for each recipient, but puts a reference to the message in each recipient's mailbox.

This means copying the mailbox, adding a reference to the message, and deleting the old mailbox. Each of these mailbox updates temporarily requires twice the size of the mailbox being updated since the mailbox is copied to a new place in the data file and the new message appended to the mailbox. For a message to many users with big mailboxes, this could easily increase, by a lot, the space temporarily required for message delivery.

In addition, a completely compressed data file tends to increase in size more quickly when it gets busy. Any new mail requires that the mailbox and the new message be appended to the end of the data file. Each new message to the same user in a short period of time means more and more space at the end of the data file, even though there is a lot of free space inside the data file, but is not big enough to accommodate the users mailbox and the new incoming message.

When a message is deleted, the user's mailbox is updated, which can use up to twice the mailbox size on disk, just like at message delivery time.

NOTE: The message and any enclosures are not actually deleted until all users have deleted the message. 3.00 3.10 Mac Server

Keywords: KB118359

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