Set-DbaMaxMemory

Synopsis

Configures SQL Server ‘Max Server Memory’ setting using calculated recommendations or explicit values

Description

Modifies the SQL Server ‘Max Server Memory’ configuration to prevent SQL Server from consuming all available system memory.
This setting controls how much memory SQL Server can allocate for its buffer pool and other memory consumers, leaving
adequate memory for the operating system and other applications.

When no explicit value is provided, the function calculates an optimal recommendation using a proven formula that reserves
memory based on total system RAM. This formula accounts for operating system overhead, scales appropriately for servers
with different memory configurations, and can handle multiple SQL Server instances on the same server.

Inspired by Jonathan Kehayias’s post about SQL Server Max memory (http://bit.ly/sqlmemcalc), this uses a formula to
determine the default optimum RAM to use, then sets the SQL max value to that number.

Jonathan notes that the formula used provides a general recommendation that doesn’t account for everything that may
be going on in your specific environment.

Syntax

Set-DbaMaxMemory
    [[-SqlInstance] <DbaInstanceParameter[]>]
    [[-SqlCredential] <PSCredential>]
    [[-Max] <Int32>]
    [[-InputObject] <PSObject[]>]
    [-EnableException]
    [-WhatIf]
    [-Confirm]
    [<CommonParameters>]

Examples

Example: 1

PS C:\> Set-DbaMaxMemory sqlserver1

Set max memory to the recommended on just one server named “sqlserver1”

Example: 2

PS C:\> Set-DbaMaxMemory -SqlInstance sqlserver1 -Max 2048

Explicitly set max memory to 2048 on just one server, “sqlserver1”

Example: 3

PS C:\> Get-DbaRegServer -SqlInstance sqlserver | Test-DbaMaxMemory | Where-Object { $_.MaxValue -gt $_.Total } | Set-DbaMaxMemory

Find all servers in SQL Server Central Management Server that have Max SQL memory set to higher than the total memory
of the server (think 2147483647), then pipe those to Set-DbaMaxMemory and use the default recommendation.

Optional Parameters

-SqlInstance

The target SQL Server instance or instances.

-SqlCredential

Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential).
Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported.
For MFA support, please use Connect-DbaInstance.

-Max

Specifies the explicit maximum memory value in megabytes for SQL Server to use. When provided, this overrides the automatic memory recommendation calculation.
Use this when you need a specific memory allocation that differs from the calculated recommendation, such as reserving memory for other applications or setting conservative limits for shared servers.

-InputObject

Accepts output objects from Test-DbaMaxMemory containing memory analysis results for one or more SQL Server instances.
Use this to pipeline memory testing results directly into memory configuration, allowing you to review recommendations before applying changes.

-EnableException

By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
This avoids overwhelming you with “sea of red” exceptions, but is inconvenient because it basically disables advanced scripting.
Using this switch turns this “nice by default” feature off and enables you to catch exceptions with your own try/catch.

-WhatIf

Shows what would happen if the cmdlet runs. The cmdlet is not run.

-Confirm

Prompts you for confirmation before running the cmdlet.