---
title: "msdb Database | Microsoft Docs"
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ms.date: "11/10/2016"
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# msdb Database
[!INCLUDE[tsql-appliesto-ss2008-xxxx-xxxx-xxx_md](../../includes/tsql-appliesto-ss2008-xxxx-xxxx-xxx-md.md)]
The **msdb** database is used by [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Agent for scheduling alerts and jobs and by other features such as [!INCLUDE[ssManStudioFull](../../includes/ssmanstudiofull-md.md)], [!INCLUDE[ssSB](../../includes/sssb-md.md)] and Database Mail.
For example, [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] automatically maintains a complete online backup-and-restore history within tables in **msdb**. This information includes the name of the party that performed the backup, the time of the backup, and the devices or files where the backup is stored. [!INCLUDE[ssManStudioFull](../../includes/ssmanstudiofull-md.md)] uses this information to propose a plan for restoring a database and applying any transaction log backups. Backup events for all databases are recorded even if they were created with custom applications or third-party tools. For example, if you use a [!INCLUDE[msCoName](../../includes/msconame-md.md)] [!INCLUDE[vbprvb](../../includes/vbprvb-md.md)] application that calls SQL Server Management Objects (SMO) objects to perform backup operations, the event is logged in the **msdb** system tables, the [!INCLUDE[msCoName](../../includes/msconame-md.md)] Windows application log, and the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] error log. To help your protect the information that is stored in **msdb**, we recommend that you consider placing the **msdb** transaction log on fault tolerant storage.
By default, **msdb** uses the simple recovery model. If you use the [backup and restore history](../../relational-databases/backup-restore/backup-history-and-header-information-sql-server.md) tables, we recommend that you use the full recovery model for **msdb**. For more information, see [Recovery Models (SQL Server)](../../relational-databases/backup-restore/recovery-models-sql-server.md). Notice that when [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] is installed or upgraded and whenever Setup.exe is used to rebuild the system databases, the recovery model of **msdb** is automatically set to simple.
> [!IMPORTANT]
> After any operation that updates **msdb**, such as backing up or restoring any database, we recommend that you back up **msdb**. For more information, see [Back Up and Restore of System Databases (SQL Server)](../../relational-databases/backup-restore/back-up-and-restore-of-system-databases-sql-server.md).
## Physical Properties of msdb
The following table lists the initial configuration values of the **msdb** data and log files. The sizes of these files may vary slightly for different editions of [!INCLUDE[ssDEnoversion](../../includes/ssdenoversion-md.md)].
|File|Logical name|Physical name|File growth|
|----------|------------------|-------------------|-----------------|
|Primary data|MSDBData|MSDBData.mdf|Autogrow by 10 percent until the disk is full.|
|Log|MSDBLog|MSDBLog.ldf|Autogrow by 10 percent to a maximum of 2 terabytes.|
To move the **msdb** database or log files, see [Move System Databases](../../relational-databases/databases/move-system-databases.md).
### Database Options
The following table lists the default value for each database option in the **msdb** database and whether the option can be modified. To view the current settings for these options, use the [sys.databases](../../relational-databases/system-catalog-views/sys-databases-transact-sql.md) catalog view.
|Database option|Default value|Can be modified|
|---------------------|-------------------|---------------------|
|ALLOW_SNAPSHOT_ISOLATION|ON|No|
|ANSI_NULL_DEFAULT|OFF|Yes|
|ANSI_NULLS|OFF|Yes|
|ANSI_PADDING|OFF|Yes|
|ANSI_WARNINGS|OFF|Yes|
|ARITHABORT|OFF|Yes|
|AUTO_CLOSE|OFF|Yes|
|AUTO_CREATE_STATISTICS|ON|Yes|
|AUTO_SHRINK|OFF|Yes|
|AUTO_UPDATE_STATISTICS|ON|Yes|
|AUTO_UPDATE_STATISTICS_ASYNC|OFF|Yes|
|CHANGE_TRACKING|OFF|No|
|CONCAT_NULL_YIELDS_NULL|OFF|Yes|
|CURSOR_CLOSE_ON_COMMIT|OFF|Yes|
|CURSOR_DEFAULT|GLOBAL|Yes|
|Database Availability Options|ONLINE
MULTI_USER
READ_WRITE|No
Yes
Yes|
|DATE_CORRELATION_OPTIMIZATION|OFF|Yes|
|DB_CHAINING|ON|Yes|
|ENCRYPTION|OFF|No|
|MIXED_PAGE_ALLOCATION|ON|No|
|NUMERIC_ROUNDABORT|OFF|Yes|
|PAGE_VERIFY|CHECKSUM|Yes|
|PARAMETERIZATION|SIMPLE|Yes|
|QUOTED_IDENTIFIER|OFF|Yes|
|READ_COMMITTED_SNAPSHOT|OFF|No|
|RECOVERY|SIMPLE|Yes|
|RECURSIVE_TRIGGERS|OFF|Yes|
|Service Broker Options|ENABLE_BROKER|Yes|
|TRUSTWORTHY|ON|Yes|
For a description of these database options, see [ALTER DATABASE (Transact-SQL)](../../t-sql/statements/alter-database-transact-sql.md).
## Restrictions
The following operations cannot be performed on the **msdb** database:
- Changing collation. The default collation is the server collation.
- Dropping the database.
- Dropping the **guest** user from the database.
- Enabling change data capture.
- Participating in database mirroring.
- Removing the primary filegroup, primary data file, or log file.
- Renaming the database or primary filegroup.
- Setting the database to OFFLINE.
- Setting the primary filegroup to READ_ONLY.
## Related Content
[System Databases](../../relational-databases/databases/system-databases.md)
[sys.databases (Transact-SQL)](../../relational-databases/system-catalog-views/sys-databases-transact-sql.md)
[sys.master_files (Transact-SQL)](../../relational-databases/system-catalog-views/sys-master-files-transact-sql.md)
[Move Database Files](../../relational-databases/databases/move-database-files.md)
[Database Mail](../../relational-databases/database-mail/database-mail.md)
[SQL Server Service Broker](../../database-engine/configure-windows/sql-server-service-broker.md)