Tested: VMware snapshot management with Snapwatcher

To monitor and manage VMware Virtual Machine Snapshots Opvizor has released a tool called Snapwatcher.  As consultant I see often that admins don’t have an overview of all the snapshots that exists in their environment. The main concerns with Virtual Machine snapshots are:

  • Snapshots are created and forgot to remove
  • Snapshots can very quickly grow in size
  • Snapshots filling datastore space
  • Delta files may cause decreased Virtual Machine and host performance

In this review Opvizor Snapwatcher is tested. With the Snapwatcher tool it is possible to centrally monitoring and managing snapshots one on more more vCenter server environments.


The installation of Snapwatcher is simple. Before installing make sure the requirements are met:

  • Windows Installer 4.5
  • Microsoft .NET Framework 4 (x86 and x64)
  • VMware vCenter 4.1 or higher

Download and  installation the Snapwatcher application.  The installation downloads the latest bits from opvizor.com and installs Snapwatcher.

1_InstallNew Update

Every time Snapwatcher is started it checks for the latest updates. So Snapwather is always up-t0-date.


The first configuration step is adding one or more vCenter Servers:

add vcenter

After adding the vCenter Server(s), thresholds on warning and error levels can be set, for example:

  • Size and age of the snapshot
  • Size and percentage of the datastore
  • Amount of snapshots for a Virtual Machine



The dashboard is divided in seperate windows. The screenshot below lists the dabboard with all the 5 windows:


Each window can be resized and re-ordered. The 5 windows displays the following information:

1. Overview of the 5 largest snapshots. The amount of snapshots displayed is configurable.

2. Snapshot Disk Waste History (GB). Displays how much disk space is wasted over a period of time.

3. Overview of all the snapshot. All the snapshots are listed with there status.  Snapshots can be sorted on VM or snapshot name, description, status, Size (GB) and created Date. Actions can performed against snapshots such as delete, fix it and exclude.

4. General overview information. Display information about the number of vCenters, ESXi servers, VMs, VMs with snapshots added, the total snapshots and snapshot size.

general info

5. Work History. Displays information about the deleted snapshots and sizes.


From the dashboard the following actions can be performed against snapshots:


Refresh: Refreshes the dashboard and perform an updated inventory of the snapshots.

Delete: Remove the snapshot from the VM.


Exclude: Snapshots can be excluded in the dashboard from displaying. This can be handy for template VM with snapshots or VMware Horizon View Linked Clones.

Fix It: Fix It repairs broken snapshots are snapshots that are not managed by the vCenter Server but are still getting used by the Virtual Machine. In the vSphere Web/Client this status is showed as “Virtual Machine disks consoldition is needed”. In Snapwatcher the status is invalid.

lx250 01 Snapshot


When the trail period (7 days) is expired it is still possible to use Snapwatcher. The following Enterprise Edition features will not work when the trail period is over:

  • Fix broken and inconsistent snapshots with our patent pending technology
  • Ignore certain VM snapshots
  • Track your VMware snapshot history


Opvizor Snapwatcher is a great tool for a VMware admin to centrally monitor and manage all the snapshots that exists in there VMware environment. Want to try Snapwatcher? Use this link.

VM snapshot needs consolidation

When a snapshot didn’t commit properly, it can happen that the snapshot manager in the vCenter server shows no snapshot(s), but that there are still active delta files on the datastore. These ‘hidden’ snapshot can cause the datastore to run out of space.

To report these ‘hidden’ snapshots (prior vSphere 5), I created a script that searches all the datastores  for ‘*.delta’ files and reported them by mail.

In vSphere 5 you have a new feature that reports and make it possible to consolidate these  ‘hidden’ snapshot(s). In vSphere 5 you get  a warning ‘Virtual machine disks consolidation is needed’ when the virtual machine snapshot consolidation has failed.


The snapshot manager shows no snapshots but there are delta files present on the datastore(s).

image image

In the vCenter server on the Virtual Machines tab you can enable the field “Needs Consolidation” to filter all the VMs that needs consolidation.


To consolidate the snapshot, right-click the virtual machine and choose Snapshot Consolidate.


Confirm the consolidate


Check the datastore and all the delta files are consolidated



With PowerCLI you can use the following one liner to list all the VMs that needs consolidation (thanks to Luc Dekens ):

Get-VM | where {$_.ExtensionData.Runtime.consolidationNeeded} | Select Name 


VMware ESXi 5 snapshot changes

In ESX(i) 3.x and 4.x snapshots files are default created in the virtual machine’s working directory (home directory). The working directory is the same directory as the were the virtual machine configuration (*.vmx) file is stored. 

snapshot-working basic esxi4


In this example a VM called “test” that has two disks (VMDK’s) placed on two datastores. The first disk is created on the VMFS01 datastore and the second disk is created on the VMFS02 datastore.  When a snapshot is created,  the VM “test”, the snapshot redolog (-delta.vmdk) files are place in the working directory (home directory). So the snapshots files are created on datastore VMFS01.


snapshot-working esxi4


In ESXi 5 the snapshot delta disks are stored in the same home folder as the base disk. On every disk a snapshot file is created.

snapshot-working esxi5


I have seen VMware ESX(i) 3.x and 4.x environments were only the working directory (home directory) is sized to store snapshot files . The other datastores didn’t have enough room for storing snapshot files.  So be sure before upgrading to vSphere 5 that all the datastores have enough free space to store snapshot files!

The snapshot location can changed in ESXi 5 but when performing a Storage vMotion, all the snapshot deltas will get migrated to the same folder as the VM’s base disk on the destination. 

Be sure to check this before upgrading to VMware vSphere 5!


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