Information Store

The information store makes it possible for users to send mail and use public folders. The information store performs the following tasks:

• Stores public folders in the public information store.
• Stores users' messages in the private information store.
• Provides rules and views.
• Maintains storage and age limits.
• Delivers messages addressed to users on the same home server as the sender.
• Forwards messages addressed to recipients on other servers and systems to the message transfer agent (MTA) to deliver.

Microsoft Exchange Server uses a fault-tolerant, transaction-based architecture for its information store.

If a power outage or other abnormal system shutdown occurs, Microsoft Exchange Server uses transaction log files to reconstruct the data. Transaction log files minimize response times for user requests and provide fault tolerance in the event that data needs to be restored.

If a message is sent to multiple mailboxes located on the same server, each person's mailbox contains a reference to a single shared copy of the message in the private information store, minimizing storage needs. This is called single-instance storage.