vSphere 6.5: Additional considerations when migrating to VMFS-6 – Part 2

In the Part 1 of this series, I was writing about the most common cases which might prevent a successful migration to VMFS-6. There is another one to cover.

For ESXi hosts that boot from a flash storage or from memory, a diagnostic core dump file can also be placed on a shared datastore. You won’t be able to un-mount this datastore without deleting a core dump first.

VMware recommends using an esxcli utility to view/edit the core dump settings. This also can be automated via PowerCLI.

To check if the core dump file exists and is active, please use the following code:

# File name: Get-VMHostCoredumpLocation.ps1
# Description: This script checks the core dump location for ESXi hosts.
# 11/10/2018 - Version 1.0
# - Initial Release
# Author: Roman Dronov (c)
# Get information about the core dump location for ESXi hosts
Write-Host "`nCore Dump Settings:`r" -ForegroundColor Green
ForEach ($vmhost in $(Get-VMHost | sort Name)) {
$esxcli2 = Get-EsxCli -VMHost $vmhost -V2
$esxcli2.system.coredump.file.get.Invoke() | Select @{N='Host Name';E={$vmhost}},@{N='Active Core Dump File';E={$_.Active}} #| Format-List
Clear-Variable vmhost,esxcli2 -Scope Global

To delete an old configuration that points to the VMFS-5 datastore, the following script can help:

# File name: Remove-VMHostCoredumpLocation.ps1
# Description: This script removes a core dump file for the particular ESXi host.
# 11/03/2019 - Version 1.0
# - Initial release
# Author: Roman Dronov (c)
# Define common functions
function ex {exit}
# Get the host name and check it is valid
$vmhosts = Get-VMHost | ? {$_.ConnectionState -eq "Connected" -or $_.ConnectionState -eq "Maintenance"} | ForEach-Object {$_.Name.Split('.')[0]}
$vmhost = (Read-Host -Prompt "`n Please type in the ESXi host name").Split('.')[0]
While ($vmhosts.Contains("$vmhost") -ne "True") {
Write-Host "`n Checking the host exists..." -NoNewline
Write-Host " The host is not reachable." -ForegroundColor Yellow
$vmhost = Read-Host -Prompt "`n Please type in the host name correctly"
$vmhost = $vmhost + "*"
# Get the system configuration
$esxcli2 = Get-EsxCli -VMHost $vmhost -V2
# Activate the current coredump (this is to identify it properly later in this script)
Write-Host "`n Searching for a coredump file and trying to activat it..." -NoNewline
$arguments = $esxcli2.system.coredump.file.set.CreateArgs()
$arguments.Item('enable') = $true
$arguments.Item('smart') = $true
Try {
$activation = $esxcli2.system.coredump.file.set.Invoke($arguments)
Catch [Exception]{
Write-Host " File doen't exist!" -ForegroundColor Yellow
# Get the current coredump configuration
$dumpConfigured = $esxcli2.system.coredump.file.get.Invoke().Configured
# Prompt for the coredump removal
If ($dumpConfigured -ne ''){
Write-Host " File exists." -ForegroundColor Green
Write-Host "`n Current configuration: $dumpConfigured"
$choice = $null
While ("Yes","No" -notcontains $choice) {
$choice = Read-Host -Prompt "`n Would you like to remove this file? (Yes/No)"
Switch ($choice){
"Yes" {
# Remove the coredump file
Write-Host " Removing the old coredump file..." -NoNewline
$arguments = $esxcli2.system.coredump.file.remove.CreateArgs()
$arguments.Item('force') = $true
$arguments.Item('file') = "$dumpConfigured"
$remove = $esxcli2.system.coredump.file.remove.Invoke($arguments)
Write-Host " Done!" -ForegroundColor Green
"No" {
# Exit this script
Write-Host "`n Exiting..."
Write-Host "`n Exiting..."

With this change made you would be able to continue migrating to VMFS-6 without any issue.

If you have any suggestions or concerns, feel free to share them in the comments below.