When initiating Delete or DeleteAll operations on snapshots, the snapshot details are deleted from Snapshot Manager, then the snapshot files are consolidated and merged to another snapshot file or to the virtual machine parent disk. If the consolidation fails, there were no snapshots shown in the Snapshot Manager, but the snapshot files were still being used on the datastore. This can cause the datastore to run out of space.
In vSphere 5.x, you are now informed when a virtual machine snapshot consolidation fails. Administrators can initiate a consolidate operation from the vSphere Client, rather than from the ESXi command line. The vSphere Client now shows a Configuration Issue warning in the Summary tab when a virtual machine snapshot consolidation fails.
Note: The ESXi host that the virtual machine is registered on must be an ESXi 5.x host.
Checking if virtual machine consolidation is required
To check if virtual machine consolidation is required:
Select a vCenter Server host or a cluster and click the Virtual Machines tab.
Right-click the menu bar for any virtual machine column and click Needs Consolidation. The Needs Consolidation column appears.
A Yes status indicates that the snapshot files for the virtual machine should be consolidated and that the virtual machine's Tasks and Events tab shows a configuration problem.
A No status indicates that the files are OK.
Note: A Configuration Issue warning is also displayed in the Summary tab of the virtual machine indicating that virtual machine disk consolidation is needed.
Consolidating snapshots for a virtual machine
To consolidate snapshots:
To consolidate the snapshot files, right-click the virtual machine and click Snapshot > Consolidate.
Check the Need Consolidation column to verify that the task succeeded.
If the task succeeded, the Configuration Issues message clears and the Needs Consolidation value is No.
Note: The consolidate option allows you to consolidate the delta disks into the base disk when there are no snapshots shown in the Snapshot Manager. It does not fix the underlying issue that may have caused this to occur initially.
There is a temporary loss of communication between the vCenter Server and the ESXi/ESX host during snapshot commit. To refresh the connectivity, restart the ESXi/ESX host management agents. For more information, see Restarting the Management agents on an ESXi or ESX host (1003490).
Additional Information
The remove snapshot process can take a long time to complete if the snapshots are large.
There may be occasions where using the Consolidate option does not work. A snapshot configuration file (with the .vmsd extension) in the virtual machine directory may interfere with consolidation of the snapshots, and it may be necessary to rename it, moved it to a new location, or delete it. For more information, see Understanding virtual machine snapshots in VMware ESXi and ESX (1015180).
The commit process has no progress that you can follow. As long as the date on the files continues to update, the process is working. Also, if the virtual machine is off, you can use the file * command to see if any files are in use.
If any of the files are locked by the consolidation process, this error message is displayed:
Can't read `filename' (Device or resource busy)
The commit process is actively being applied to those files.
