--- title: "Instance Configuration | Microsoft Docs" ms.custom: "" ms.date: 05/04/2016 ms.prod: "sql-server-2014" ms.reviewer: "" ms.technology: install ms.topic: conceptual f1_keywords: - "instance configuration, Setup" helpviewer_keywords: - "Instance Name page [SQL Server Installation Wizard]" - "SQL Server Installation Wizard, Instance Name page" ms.assetid: 5bf822fc-6dec-4806-a153-e200af28e9a5 author: MashaMSFT ms.author: mathoma manager: craigg --- # Instance Configuration Use the **Instance Configuration** page of the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Installation Wizard to specify whether to create a default instance or a named instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]. If an instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] is not already installed, a default instance will be created unless you specify a named instance. Each instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] consists of a distinct set of services that have specific settings for collations and other options. The directory structure, registry structure, and service names all reflect the instance name and a specific instance ID created during [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Setup. An instance is either the default instance or a named instance. The default instance name is MSSQLSERVER. It does not require a client to specify the name of the instance to make a connection. A named instance is determined by the user during Setup. You can install [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] as a named instance without installing the default instance first. Only one installation of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)], regardless of version, can be the default instance at one time. **Alert!** With [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] SysPrep, you can specify the instance name when you complete a prepared instance on the **Instance Configuration** page. You can choose to configure the prepared instance you are completing as a default instance if there is no existing default instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] on the machine. ## Multiple Instances [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] supports multiple instances of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] on a single server or processor, but only one instance can be the default instance. All others must be named instances. A computer can run multiple instances of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] concurrently, and each instance runs independently of other instances. For more information, see [Maximum Capacity Specifications for SQL Server](../maximum-capacity-specifications-for-sql-server.md). ## Options Failover cluster instances only - Specify the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] failover cluster network name. This name identifies the failover cluster instance on the network. Default or Named instance - Consider the following information when you decide whether to install a default or named instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]: - If you plan to install a single instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] on a database server, it should be a default instance. - Use a named instance for situations where you plan to have multiple instances on the same computer. A server can host only one default instance. - Any application that installs [!INCLUDE[ssExpress](../../includes/ssexpress-md.md)] should install it as a named instance. This will minimizes conflict when multiple applications are installed on the same computer. **Default instance** Select this option to install a default instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]. A computer can host only one default instance; all other instances must be named. However, if you have a default instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] installed, you can add a default instance of [!INCLUDE[ssASnoversion](../../includes/ssasnoversion-md.md)] to the same computer. **Named instance** Select this option to create a new named instance. Be aware of the following when you name an instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]: - Instance names are not case sensitive. - Instance names cannot start or end with an underscore (_). - Instance names cannot contain the term "Default" or other reserved keywords. If a reserved keyword is used in an instance name, a Setup error will occur. For more information, see [Reserved Keywords (Transact-SQL)](/sql/t-sql/language-elements/reserved-keywords-transact-sql). - If you specify MSSQLServer for the instance name, a default instance will be created. - An installation of [!INCLUDE[ssGeminiLong](../../includes/ssgeminilong-md.md)] is always installed as a named instance of 'PowerPivot'. You cannot specify a different instance name for this feature role. - Instance names are limited to 16 characters. - The first character in the instance name must be a letter. Acceptable letters are those defined by the Unicode Standard 2.0. These include Latin characters a-z, A-Z, and letter characters from other languages. - Subsequent characters can be letters defined by the Unicode Standard 2.0, decimal numbers from Basic Latin or other national scripts, the dollar sign ($), or an underscore (_). - Embedded spaces or other special characters are not allowed in instance names. The backslash (\\), comma (,), colon (:), semi-colon (;), single quote ('), ampersand (&), hyphen (-), and at sign (@) are also not allowed. - **Only characters that are valid in the current Windows code page can be used in [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] instance names. If an unsupported Unicode character is used, a Setup error will occur.** **Detected instances and features** View a list of installed [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] instances and components on the computer where [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Setup is running. **Instance ID** - By default, the instance name is used as the Instance ID. This is used to identify installation directories and registry keys for your instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]. This is the case for default instances and named instances. For a default instance, the instance name and instance ID would be MSSQLSERVER. To use a non-default instance ID, specify it in the **Instance ID** field. > [!IMPORTANT] > With [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] SysPrep, the Instance ID displayed on this page is the Instance ID specified during the prepare image step of the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] SysPrep process. You will not be able to specify a different Instance ID during the complete image step. > [!NOTE] > Instance IDs that begin with an underscore (_) or that contain the number sign (#) or the dollar sign ($) are not supported. For more information about directories, file locations, and instance ID naming, see [File Locations for Default and Named Instances of SQL Server](../../../2014/sql-server/install/file-locations-for-default-and-named-instances-of-sql-server.md). All components of a given instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] are managed as a unit. All [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] service packs and upgrades will apply to every component of an instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]. All components of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] that share the same instance name must meet the following criteria: - **Same version** - **Same edition** - **Same language settings** - **Same clustered state** > [!NOTE] > [!INCLUDE[ssRSnoversion](../../includes/ssrsnoversion-md.md)] is not cluster-aware. - **Same operating system**