XFOR: Many DAT Files in the Mtadata Directory
Article ID: 178021
Article Last Modified on 10/28/2006
APPLIES TO
- Microsoft Exchange Server 5.5 Standard Edition
This article was previously published under Q178021
SYMPTOMS
When you look in the Microsoft Exchange Server Mtadata directory, you may
find a large number of .dat files, for example, DB000123.DAT. Many of these
files are only 1 byte in size. This is also true, even if the Exchange
Server message transfer agent (MTA) does not have any messages in the
queues held for delivery.
CAUSE
This is by product design. In Microsoft Exchange Server 5.5, the MTA
creates DAT files for all messages. After the messages have been delivered,
instead of deleting the DAT files themselves, the data is deleted from the
DAT files and the files are reset to 1 byte. The DAT files can be reused
for future messages. This is done to enhance the performance of the MTA
because creating and deleting files is a time consuming process. The number
of .dat files will reflect the maximum number of messages in the queue at
any one time.
Keywords: kbusage KB178021