We are having VMware ESXi 4.1 and we need to move to ESXi 5.1 or ESXi 5.5.

Before upgrade some of our team members advised us to take a backup of VMs.

Now the problem is we don't have SAN or Net app storage. We are having another ESXi server with enough space to hold 15 VMs.

We are having VMs with snapshots.

Using VMware converter i can copy those VMs to the back up server. But i am not sure whether it will take backup of our snapshots as well.

Do we need to take backup before upgrade? If needed to take backup which mechanism is better to take backup with snapshots.

  • Are you using vCenter? Are you using shared storage? Or is it really one ESX server and a second one standby in case of a disaster? – Marki Feb 9 '14 at 16:42
  • It would be great if you would in some way follow up to your questions and answers and at least select one answer as accepted... – Marki Mar 3 '14 at 20:33

You don't need to back up your VM datastores when upgrading between versions of the VMware software. Your local VMFS datastores won't be overwritten by the upgrade process...

You should have a backup solution in place in general to protect yourself from complete hardware failure and other emergencies. But that's a more complex topic.


Backing up would essentially mean shut down your VMs and copy all the files from the VMFS to somewhere else. Copying everything would include the snapshots.

If this is a standalone host

You need to backup and restore anyway because if you want to actually upgrade the VMFS you can't do this without creating a new one, meaning trashing the old one if you don't have space somewhere else.

If these are a few servers with shared storage

In order to upgrade to ESX5 you would first upgrade vCenter or install a new one and reattach the servers to it. A newer vCenter can talk to older and newer ESX versions.

Then you vMotion the VMs away from the host to be upgraded, and frankly I would simply reinstall that host with the new version and not play with Update Manager or the like.

You need not immediately convert the datastores nor do you need to upgrade the VM Hardware rightaway. Those would be the steps once you know that the new ESX version works fine for you.

Then you would

  • create new datastores for VMFS5 (upgrading to VMFS5 does not really make them become a full-fledged VMFS5)
  • storage vmotion or copy the old data to them
  • delete the VMFS3s and create new VMFS5s in their place

Finally you will at some time need to

  • upgrade VMware Tools
  • the VM Hardware version but these will require shutting down/restarting the VMs.

In summary, the kind of downtime you need depends on the amount of hardware you have (one or more servers) and your VMware licenses (multiple ESX hosts, vCenter, Storage vMotion, ...).


Backup before upgrade is always a best practice. But not necessarily easy to realize.

If you can shut the VMs down, I'd recommend simply to copy the files in the datastores before upgrading (you don't need to shut all vms at the same time). That's the easiest and safest way to go.

If you can't shut the VMs down, then use the snapshot features to externalize the VMs but that usually requires a second tool (like converter or third party backup like veeam).

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