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Archive for May, 2013

Getting and Setting Path Selection Policies with PowerCLI

May 26th, 2013 No comments

A colleague I work with was looking for a script that would list all disk devices on ESXi hosts that were not set to Round Robin. After this, he wanted to be able to set all of these to the Round Robin Path Selection Policy (PSP). The two tasks can actually be achieved really easily with just a few lines of PowerCLI.

Getting disk devices on all ESX hosts that do not use the Round Robin PSP:

$AllESXHosts = Get-VMHost | Where { ($_.ConnectionState -eq "Connected") -or ($_.ConnectionState -eq "Maintenance")} | Sort Name
Foreach ($esxhost in $AllESXHosts) {
	Get-VMhost $esxhost | Get-ScsiLun -LunType disk | Where { $_.MultipathPolicy -notlike "RoundRobin" } | Select CanonicalName,MultipathPolicy
}

To set the path selection policy to something else, it is a simple modification of the above to add the Set-ScsiLun cmdlet:

 

$AllESXHosts = Get-VMHost | Where { ($_.ConnectionState -eq "Connected") -or ($_.ConnectionState -eq "Maintenance")} | Sort Name
Foreach ($esxhost in $AllESXHosts) {
	Get-VMhost $esxhost | Get-ScsiLun -LunType disk | Where { $_.MultipathPolicy -notlike "RoundRobin" } | Set-ScsiLun -MultipathPolicy "RoundRobin"
}

There are quite a few scripts floating around out there that achieve similiar results, but I thought I would do my own take on this task. Below is my full script that offers a simple menu system with two options, one to list/log all current path selection policies on hosts that are not round robin to a timestamped log file, and one to set all path selection policies not round robin, to round robin and log these.

 

# Description:  Offers to either check and log path selection policies not set to RoundRobin, OR, set and log these disk PSPs to RoundRobin
# Author: Sean Duffy
# Web/blog: http://www.shogan.co.uk
# Date: 25/05/2013
## IMPORTANT: Always test scripts in preproduction or your lab before using them live!!

#region UserDefined
# Setup the location of our log files...
# This should be the only custom bit you need to set (the location you want log files to be)
# This will only be used when changing path selection policies
$SetPSPlogfile = "C:\temp\SetPathSelectionPolicy_UpdateScript_Log.txt"
# This will only be used when seeing what path selection policies are in place that are not round robin
$GetPSPlogfile = "C:\temp\GetPathSelectionPolicy_UpdateScript_Log.txt"
#endregion

# Ask for connection details, then connect using these
$vcenter = Read-Host "Enter vCenter Name or IP"
$username = Read-Host "Enter your username"
$password = Read-Host "Enter your password"
$Connection = Connect-VIServer $vcenter -User $username -Password $password

# Grab all ESX hosts on the connection that are either connected, or connected and in maintenance mode
$AllESXHosts = Get-VMHost | Where { ($_.ConnectionState -eq "Connected") -or ($_.ConnectionState -eq "Maintenance")} | Sort Name

# Prompt user with two options - 1) List all disk devices where no roundrobin PSP is set, or 2) Change all disk devices to RoundRobin PSP
Clear
Write-Host "1) Log all disk devices on all hosts where RoundRobin not set." -ForegroundColor Yellow
Write-Host "2) Set and log all disk devices on all hosts where RoundRobin not set, to RoundRobin." -ForegroundColor Yellow
$MenuChoice = Read-Host "Enter your selection (1/2)"

# We could use a switch statement here too, but an if,elseif,else statement is fine in this case...
# Chose option 1
if ($MenuChoice -like "1") {
	# Log the username to our log file
	$User = $Connection.User
	Write "User logged in for reading of PSPs: $User" | Out-File $GetPSPlogfile -Append
	Write-Host "Paths not set to RoundRobin for each host will be logged to the $GetPSPlogfile"
	Foreach ($esxhost in $AllESXHosts) {
		# Write an entry into our log for the host we busy reading PSPs from
		$Now = Get-Date
		Write "$Now :: Getting paths on $esxhost where not set to RoundRobin" | Out-File $GetPSPlogfile -Append
		Write-Host "ESX Host: $esxhost :: Disk devices not set to RoundRobin" -ForegroundColor Cyan
		Get-VMhost $esxhost | Get-ScsiLun -LunType disk | Where { $_.MultipathPolicy -notlike "RoundRobin" } | Select CanonicalName,MultipathPolicy | Out-File $GetPSPlogfile -Append
	}
	Write "------------- End of this run -------------" | Out-File $GetPSPlogfile -Append
	Disconnect-VIServer * -Confirm:$false
}
# Chose option 2
elseif ($MenuChoice -like "2") {
	# Prompt user with a warning first and ask to confirm to continue as this is a change to policies...
	Write-Host "WARNING: You are about to loop through all ESX hosts found and change disks to a PSP of RoundRobin! 
	Are you sure you want to continue? (Y/N): " -ForegroundColor Yellow -NoNewline
	$Answer = Read-Host

	# If user answered y, or Y, then continue with the change...
	if ($Answer -like "y") {
		# Log the username to our log file
		$User = $Connection.User
		Write "User logged in for change: $User" | Out-File $SetPSPlogfile -Append
		# Loop through all ESX hosts
		Foreach ($esxhost in $AllESXHosts) {
			# Write an entry into our log for the host we are working on along with the current timestamp
			$Now = Get-Date
			Write "$Now :: Setting PSP for the following current devices on $esxhost to RoundRobin" | Out-File $SetPSPlogfile -Append
			Write-Host "ESX Host: $esxhost :: Now setting path selection policy for all disk devices that are not already set to RoundRobin, to RoundRobin" -ForegroundColor Cyan
			# Find all disk devices where they are not already set to Round Robin Path Selection Policy and log these to log file
			Get-VMHost $esxhost | Get-ScsiLun -LunType disk | Where { $_.MultipathPolicy -notlike "RoundRobin" } | Select CanonicalName,MultipathPolicy | Out-File $SetPSPlogfile -Append
			# Find all disk devices where they are not already set to Round Robin Path Selection Policy and set these to RoundRobin
			Get-VMhost $esxhost | Get-ScsiLun -LunType disk | Where { $_.MultipathPolicy -notlike "RoundRobin" } | Set-ScsiLun -MultipathPolicy "RoundRobin"
		}
		Write "------------- End of this run -------------" | Out-File $SetPSPlogfile -Append
		Disconnect-VIServer * -Confirm:$false
	}
	else {
		Disconnect-VIServer * -Confirm:$false
		Write-Host "Script aborted" -ForegroundColor White
	}
}
# Didn't enter a valid choice...
else {
	Disconnect-VIServer * -Confirm:$false
	Write-Host "Not a valid choice! Exiting script..."
}