Mac Srv: Mail Data Files Can Increase in Size Quickly (118359)
The information in this article applies to:
- Microsoft Mail for AppleTalk Networks 3.0
- Microsoft Mail for AppleTalk Networks 3.1
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
| Modification Type: | Major | Last Reviewed: | 10/30/2003 |
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| Keywords: | KB118359 |
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