By Alison / Last Updated April 24, 2022

Error: VMware Virtual machine disks consolidation is needed

If you see the VMware error: “virtual machine disks consolidation is needed” in Summary tab on vSphere 5, 6.5, 6.7, or 7, for most times it means that the snapshot deletion process is not completed successfully.

VMware error: virtual machine disk consolidation is needed

In this article, I will analyze what possible reasons lead to this error, and provide 2 proven ways to solve it.

This article covers:

What is virtual machine disk consolidation

In general, virtual disk consolidation is a process of merging snapshots into the original virtual machine.

Taking a VMware snapshot will make the original virtual disk file read-only, and create a delta disk file to store all changes made to the VM afterwards. The more and longer the snapshots are kept, the more redundant data will be. Snapshot files can take up large disk space and even affect the original VM performance. Therefore, virtual machine disk consolidation is needed to merge snapshots and remove redundant data.

Deleting VMware snapshots properly via Snapshot Manager will merge them to the original virtual disk, while deleting snapshots incorrectly can be very dangerous. If you just accidentally deleted the descriptor files, there’s still a way to recover the deleted VMware snapshot. However, if the snapshot data files are deleted directly, it may result in data loss.

Possible reasons for virtual machine disk consolidation needed error

As I mentioned, it is the incomplete snapshot deletion that caused the VMware error: virtual machine disk consolidation is needed. Except for incorrect operations, there are still other reasons why a snapshot deletion fails to complete successfully. For example:

  • Connection issues between the ESXi host and vCenter server.
  • Lack of VMFS disk space for consolidating the snapshot and the original virtual disk.
  • Poor storage performance, large or timeout snapshots may not be successfully deleted.
  • Snapshot files are locked, for example, you cannot successfully delete the snapshot while a third-party software is backing up the VM.

How to fix VMware error: virtual machine disk consolidation is needed

To solve the VMware virtual machine disk consolidation is needed error, you just need to perform the disk consolidation as it mentioned.

In this section, I will introduce 2 proven ways to do this.

Manually consolidate virtual disks via VMware ESXi web client

1. Access to VMware ESXi web client, and navigate to Virtual Machines from the left inventory.

2. Right-click on the VM name and select Snapshots > Consolidate disks.

Perform disk consolidation on web client

3. Click Yes to confirm disk consolidation of the VM.

Confirm-disk-consolidation

Using PowerCLI to perform VMware VM disk consolidation

1. Connect to vCenter server and provide relevant credentials:

Connect-VIServer -Server [server name] -Protocol [http] -User [user name] -Password [password]

2. Check which VM needs disk consolidation:

Get-VM | Where-Object {$_.Extensiondata.Runtime.ConsolidationNeeded}

3. Consolidate the disk of a specific virtual machine called MyVM:

(Get-VM -Name "MyVM").ExtensionData.ConsolidateVMDisks()

Tip: To consolidate all virtual machines that need disk consolidation:
Get-VM | Where-Object {$_.Extensiondata.Runtime.ConsolidationNeeded} | foreach {$_.ExtensionData.ConsolidateVMDisks_Task()}

Best Practices for using VMware snapshot

As you can see, incorrectly using VMware snapshots may result in errors. In addition, snapshots can have a negative impact on the performance of VM systems.

For better working with VMware snapshots, here I summarized 3 best practices.

Do not use VMware snapshots as backups

It is commonly accepted that VM snapshot and backup cannot replace each other. Snapshots depend on the parent disk, if the parent disks are deleted, the snapshot files are not sufficient to restore a VM.

But VM backup is an independent copy of the VM, it can be safely stored offsite, to the cloud, or other locations. Restore from it you will gain an instant usable VM.

Use only 2-3 snapshots for each VM

Actually, maximum of 32 snapshots are supported in a chain. However, the more snapshots you kept, the more they affect the VM performance.

Therefore, for a better performance please use only 2 to 3 snapshots.

Do not use a single snapshot for more than 72 hours

For most times, you need to reserve 20-30% extra storage for a single snapshot. The longer you keep these snapshots, they will take more disk space and thus affect the performance of your VM.

It is recommended by VMware that do not to keep snapshots for more than 72 hours. Therefore, it is necessary to delete the snapshots in time to merge the changes to the parent disk when they are no longer useful, or before creating backups of your VM.

Auto backup software that can effectively avoid manual errors

Just like the VMware VM disk consolidation error, manually backup VMware VMs may also result in many other errors. Therefore, to avoid manual errors, many IT staffs turn to dedicated backup tools that can backup VMs automatically.

Here I recommend you AOMEI Cyber Backup for the following benefits:

Auto Execution: capable of backing up multiple VMs automatically, and cleaning old backup files that exceed the specified retention period.
Role Assignment: allows one administrator to create sub-accounts with limited privileges, effectively avoid errors caused by others’ mis-operations.
Offsite Restore: capable of restoring backups to new VMs on original or another datastore, host.
Affordable Pricing: reasonable charges only based on the number of bound devices, regardless of how many VMs are on the host.

In next section I will demonstrate how to create an automatic backup task of multiple ESXi VMs. You can click the following button to start a free trial.

Download Free TrialVMware ESXi 6.0 & later versions
Secure Download

3 easy steps to create automatic backup tasks of multiple VMs

1. Bind Devices: Access to AOMEI Cyber Backup web client, navigate to Source Device > VMware ESXi > + Add VMware ESXi to add a host. And then click > Bind Device.

Tip: Except for VMware ESXi, it also supports Hyper-V VM backup. The supported versions are: VMware ESXi 6.0 and all later versions, Windows Server 2012 and all later versions.

Add VMware ESXi host

2. Create Backup Task: Navigate to Backup Task > + Create New Task, and then set Task Name, Backup Type, Device, Target, Schedule, and Cleanup.

  • Device: using AOMEI Cyber Backup you can backup multiple, or even all VMs on the host at once.
  • Target: You can select to back up to a local path, or to a network path. Used paths will be saved in Favorite Storage for handy selection.
  • Schedule: You can choose to perform full, differential or incremental backup, and automate execution daily, weekly or monthly according to the frequency you specified.
  • Cleanup: You can specify a retention period, and the old backup files that exceed the period will be automatically deleted.

3. Start Backup: You can select Add the schedule and start backup now, or Add the schedule only.

Create a VMware ESXi backup task

Created backup tasks will be listed and monitored separately, for progress checking and schedule changing.

Restore VMware ESXi VM to new location

Summary

The VMware “virtual machine disk consolidation is needed” error is commonly caused by incomplete of snapshot deletion. To fix this, I introduced 2 methods of how to do virtual machine disk consolidation in VMware in this article.

Just like large VMware snapshot size can result in performance degradation, incorrect snapshot deletion can even cause data loss. Therefore, I also summarized 3 best practices for using snapshots. If you want to further protect your VM data from accidental mis-operations, especially from manual errors, some professional backup software may be very helpful.