Riker1964
Contributor
Contributor

Snapshots question...

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Author : Martina Laleva

URL : http:////docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.vm_admin.doc/GUID-2F4A6D8B-33FF-4C...

Topic Name : Consolidate Snapshots

Publication Name : vSphere Virtual Machine Administration

Product/Version : VMware vSphere/6.5

Question :

I took a look at my VMs today and some have a snapshot created back in Sept and BELOW the snapshot entry is YOU ARE HERE. Not sure how they got there. All VMs should be showing YOU ARE HERE only, because I don't use snapshots, outside of backups. So on a TEST VM, I deleted the snapshot and vCenter showed the display as broken. I then powered off the VM, and vCenter showed that it needed consolidation. So I did that, and powered back up. Now that looks normal, showing only YOU ARE HERE. I have a Domain Controller, and Exchange Server, and a Misc server showing the same thing. Can I perform the same procedure on these onther VMs to get them back to normal - SAFELY? What is happening when I delete the snapshot and consolidate? Am I putting old data back into the live VM? How did this occur in the first place? Any advice would be greatly appreciated.

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Accepted Solutions
sk84
Expert
Expert

If you delete a snapshot all changes since snapshot creation are merged into the live VM. Or in other words, you keep the current state and no data will be changed.

If you revert a snapshot all changes since snapshot creation are rolled back.

In general, it's a safe task and can be done while the virtual machine is running. However, because it's an IO intensive task, virtual machines can sometimes freeze for a short time. This depends on your storage and how large the snapshots are and how sensitive your workloads react to IO operations.

--- Regards, Sebastian VCP6.5-DCV // VCP7-CMA // vSAN 2017 Specialist Please mark this answer as 'helpful' or 'correct' if you think your question has been answered correctly.

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7 Replies
sk84
Expert
Expert

If you delete a snapshot all changes since snapshot creation are merged into the live VM. Or in other words, you keep the current state and no data will be changed.

If you revert a snapshot all changes since snapshot creation are rolled back.

In general, it's a safe task and can be done while the virtual machine is running. However, because it's an IO intensive task, virtual machines can sometimes freeze for a short time. This depends on your storage and how large the snapshots are and how sensitive your workloads react to IO operations.

--- Regards, Sebastian VCP6.5-DCV // VCP7-CMA // vSAN 2017 Specialist Please mark this answer as 'helpful' or 'correct' if you think your question has been answered correctly.
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a_p_
Leadership
Leadership

Welcome to the Community,

In addition to what sk84​ already mentioned, please be patient when you delete snapshots. Depending on their size, deleting them may take quite some time.

If you don't need any snapshots, and want to keep the VM in its current state, consider to use "Delete All" from the Snapshot Manager.

Please remember that deleting snapshots for VMs with thin provisioned virtual disks may require additional (temporary) free disk space on the datastore!

André

Riker1964
Contributor
Contributor

Thank you! DELETE ALL snapshots seems to have taken care of it for me. Kept the VM live as well. I will have to monitor this in the future, not sure how these snapshots got created.

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a_p_
Leadership
Leadership

In case it helps. Take a look at  RVTools (https://www.robware.net/rvtools/), which is a great (free) tool to that gives you an overview of the environment.

André

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Riker1964
Contributor
Contributor

Is this "Delete all snapshots" command still safe to do on a VM that is a Domain Controller, as well?

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sk84
Expert
Expert

From VMware's perspective, it's the same for all VMs. Because your VMware infrastructure doesn't know what a VM is used for.

You need to be able to judge if the workload in your VM is IO-sensitive and how much performance your storage has. In my experience, domain controllers are not very IO heavy, so I don't think it's a problem.

--- Regards, Sebastian VCP6.5-DCV // VCP7-CMA // vSAN 2017 Specialist Please mark this answer as 'helpful' or 'correct' if you think your question has been answered correctly.
UteTech
Contributor
Contributor

With a thin provisioned virtual disk, does the (temporary) free disk space on the datastore that is used get freed up at some point? This seems to be occurring in my environment as it is thin provisioned and I deleted a snapshot that was two years old. 

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