functions/Get-DbaMaxMemory.ps1

Function Get-DbaMaxMemory
{
<#
.SYNOPSIS
Gets the 'Max Server Memory' configuration setting and the memory of the server. Works on SQL Server 2000-2014.

.DESCRIPTION
This command retrieves the SQL Server 'Max Server Memory' configuration setting as well as the total physical installed on the server.

.PARAMETER SqlServer
Allows you to specify a comma separated list of servers to query.

.PARAMETER SqlCredential
Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted. To use:

$cred = Get-Credential, then pass $cred variable to this parameter.

Windows Authentication will be used when SqlCredential is not specified. To connect as a different Windows user, run PowerShell as that user.

.NOTES
dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
Copyright (C) 2016 Chrissy LeMaire

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

.LINK
https://dbatools.io/Get-DbaMaxMemory

.EXAMPLE
Get-DbaMaxMemory -SqlServer sqlcluster,sqlserver2012

Get memory settings for all servers within the SQL Server Central Management Server "sqlcluster".

.EXAMPLE
Get-DbaMaxMemory -SqlServer sqlcluster | Where-Object { $_.SqlMaxMB -gt $_.TotalMB }

Find all servers in Server Central Management Server that have 'Max Server Memory' set to higher than the total memory of the server (think 2147483647)

#>

    [CmdletBinding()]
    Param (
        [parameter(Position = 0, Mandatory = $true, ValueFromPipeline = $True)]
        [Alias("ServerInstance", "SqlInstance", "SqlServers")]
        [object]$SqlServer,
        [System.Management.Automation.PSCredential]$SqlCredential
    )
    
    PROCESS
    {
        $collection = @()
        foreach ($servername in $sqlserver)
        {    
            Write-Verbose "Attempting to connect to $servername"
            try
            {
                $server = Connect-SqlServer -SqlServer $servername -SqlCredential $SqlCredential
            }
            catch
            {
                Write-Warning "Can't connect to $servername or access denied. Skipping."
                continue
            }

            $totalmemory = $server.PhysicalMemory
            
            # Some servers under-report by 1MB.
            if (($totalmemory % 1024) -ne 0) { $totalmemory = $totalmemory + 1 }

            [pscustomobject]@{
                Server = $server.name
                TotalMB = $totalmemory
                SqlMaxMB = $server.Configuration.MaxServerMemory.ConfigValue
            }
        }
    }
}