Deleting a snapshot removes the snapshot from the Snapshot Manager. The snapshot files are consolidated and written to the parent snapshot disk and merge with the virtual machine base disk. You can use the Snapshot Manager to delete a single snapshot or all snapshots in a snapshot tree.
Deleting a snapshot does not change the virtual machine or other snapshots. Deleting a snapshot consolidates the changes between snapshots and previous disk states and writes all the data from the delta disk that contains the information about the deleted snapshot to the parent disk. When you delete the base parent snapshot, all changes merge with the base virtual machine disk.
To delete a snapshot, a large amount of information needs to be read and written to a disk. This process can reduce virtual machine performance until consolidation is complete. Consolidating snapshots removes redundant disks, which improves virtual machine performance and saves storage space. The time it takes to delete snapshots and consolidate the snapshot files depends on the amount of data that the guest operating system writes to the virtual disks after you take the last snapshot. The required time is proportional to the amount of data the virtual machine is writing during consolidation if the virtual machine is powered on.
Failure of disk consolidation can reduce the performance of virtual machines. You can check whether any virtual machines require separate consolidation operations by viewing a list. For information about locating and viewing the consolidation state of multiple virtual machines and running a separate consolidation operation, see vSphere Virtual Machine Administration.
Use the Delete option to remove a single parent or child snapshot from the snapshot tree. Delete writes disk changes that occur between the state of the snapshot and the previous disk state to the parent snapshot.
Deleting a single snapshot preserves the current state of the virtual machine and does not affect any other snapshot.
You can also use the Delete option to remove a corrupt snapshot and its files from an abandoned branch of the snapshot tree without merging them with the parent snapshot.
Use the Delete All option to delete all snapshots from the Snapshot Manager. Delete all consolidates and writes the changes that occur between snapshots and the previous delta disk states to the base parent disk and merges them with the base virtual machine disk.
To prevent snapshot files from merging with the parent snapshot if, for example, an update or installation fails, first use the Restore command to restore to a previous snapshot. This action invalidates the snapshot delta disks and deletes the memory file. You can then use the Delete option to remove the snapshot and any associated files.
Use care when you delete snapshots. You cannot restore a deleted snapshot. For example, you might want to install several browsers, a, b, and c, and capture the virtual machine state after you install each browser. The first, or base snapshot, captures the virtual machine with browser a and the second snapshot captures browser b. If you restore the base snapshot that includes browser a and take a third snapshot to capture browser c and delete the snapshot that contains browser b, you cannot return to the virtual machine state that includes browser b.
Ensure that you are familiar with the Delete and Delete all actions and how they might affect virtual machine performance.
- Right-click the virtual machine and select Manage Snapshots.
- To locate a virtual machine, select a datacenter, folder, cluster, resource pool, host, or vApp.
- Click the VMs tab and click Virtual Machines.
- In the Snapshot Manager, click a snapshot to select it.
- Select whether to delete a single snapshot or all snapshots.
Consolidates the snapshot data to the parent snapshot and removes the selected snapshot from the Snapshot Manager and virtual machine.
Consolidates all of the immediate snapshots before the You are here current state to the base parent disk and removes all existing snapshots from the Snapshot Manager and virtual machine.
- Click Yes in the confirmation dialog box.
- Click Close to exit the Snapshot Manager.