Saturday, 30 April 2016

Difference Between Exchange EDB and STM File

Microsoft Exchange Server has two elementary components, which are Storage Group and Databases. The Storage Group is known as a container used for keeping Mailboxes and Public Folder Store. Storage Group on the other hand contains multiple data stores and each data store is somewhere associated with Exchange Server.
When a new Exchange Server is installed, the two data stores Mailboxes and Public Folder are created initially as default stores. This default Mailbox store contains two database files:

1. Priv1.edb and
2. Priv1.stm

From here, the two file formats appear into the scene.

Priv1.edb is a rich text file that includes message headers, message text, and standard attachments.

Priv1.stm is a file that contains streaming internet content, which includes audio, video and MIME data.

What are EDB Files or .edb File Extension?

Exchange Database files are known as EDB files, which were designed on single client server architecture. Moreover, .edb is the file extension of the Exchange database or EDB files. These files contain rich text data stored in Exchange Server and Exchange Server uses Extensible Storage Engine (ESE) in order to access files that are stored in .edb extension. Components that an .edb file contains are email, message, folders and attachments. EDB files have unique file signature, i.e. Hexadecimal ef cd 89. The earlier version of Exchange stores emails in two types of EDB files. One is priv1.edb, which keeps only private data of user mailboxes. Second is pub1.edb, which keeps shared folder data of user mailboxes. To access the EDB file you can use the Exchange EDB Viewer tool.

What Are STM Files or .stm File Extension?

The Streaming data file .stm were created in Exchange 2003 and previous version to save email attachments including some information so that it will be added “on the fly” before it is sent to you, typically it is used in order to include last modified date at the bottom of the page. Only certain application can launched Files that have .stm file extension. STM files can’t be viewed at all, as they are data files rather than document or media files. They store the internet MIME formatted content like, images, audio, video etc. Streamed database is saved here. In addition, in order to optimize the performance of application for the type of database it stores Microsoft provides this file format. However, unfortunately after Exchange 2003 edition STM file was excluded from the database structure.

Difference Between Exchange EDB and STM File?

1. The fundamental B-Tree structure is present in .edb file whereas it is not present in .stm file.

2. .edb file permits a top-level node and many child nodes but .stm file does not permit any node.

3. The .edb file is accessed directly by ESE whereas one cannot access .stm file directly.

4. The .stm file is used in conjunction with .edb file to comprise the exchange database.

5. Both .edb and .stm file together make up the database, therefore they are treated as a single entity.

6. If you do some changes or perform any action on the .edb file the .stm file is automatically included.

7. The main purpose of .stm file is to store the streamed internet content whereas .edb file store database information.

8. Whenever you move messages to .edb file and convert it to Exchange native form it can never be moved back to .stm.


This blog is aimed to bring into the user’s awareness about the EDB and STM file. The segment discusses how these files came into picture and in what scenarios are they different from each other though they are part of Exchange. Moreover, the purpose of using Priv1.edb and Pub1.edb files are used.


Post a Comment