How to take and use vm snapshots

[ndubula]

I am using VMware vSphere 4.0.0 and have a number of vms running windows and linux. Now, how do I take and use the snapshots of the vms, can someone help I am new to virtualization.

[RvdNieuwendijk]

Welcome to the VMware VMTN Communities.

You can take a snapshot of a virtual machine in the vSphere client by selecting the virtual machine and then clicking on the "Take a snapshot of this virtual machine" button in the button bar. You can revert to or delete a snapshot by clicking on the "Snapshot Manager" button in the button bar.

[ndubula]

Hi,

Thanks for the reply. My question is basically resulting from the storage problems I have. You have mentioned that I click on the vm and select take snapshot of this vm, then what are the next steps, and how am i going to use the snapshot afterwards? Do I use the snapshot whwn a vm clashes? Thans once again

[RvdNieuwendijk]

A snapshot of a virtual machine is like a point in time that you can go back to. For instance you can make a snapshot of a virtual machine before you install a new software product. If the installation is successful you can delete the snapshot. If the installation fails you revert to the snapshot and have the state of the virtual machine back before you tried to install the software.

Using a snapshot when a vm clashes depends on what you have done in the vm after making the snapshot. Remember that by reverting to the snapshot you will loose everything that has changed in the vm after you made the snapshot.

It is possible to create a tree of snapshots and switch between them.

Having a snapshot is bad for the performance of the virtual machine. So it is best practice to not have many snapshots for one vm and not keeping them for a long time.

Message was edited by: RvdNieuwendijk Modified some typos.

[ndubula]

Your explanation is actually opening my eyes. I am having a hard time differentiating between snapshot and cloning a vm, which one should I rely on without affecting the performance of the cm?

My problem here is actually on the best way to stay safe in case a system class happens, what would you advise me to do in the following scenario?

I have a host that have three vms each has a vHDD of 250GB, now, what should I do so that in case any of these vms clashes, then restoring the system to allow users continue working wont take a long time. Is that backup, snapshot or cloning? Please advise. Also backing up the 250GB vm takes a long time, are there other better options? Thanks.

[RvdNieuwendijk]

If you make a clone of a vm, the clone will not affect the performance of the vm. But the clone will take the same amount of disk space as the original vm does.

A snapshot will start small and grows as more blocks are changed in the vm's disks.

Snapshots and cloning are not very good solutions for data recovery. Think about what would happen if something goes wrong with your storage device. You will lose the vm's disks and the clones or snapshots. I would recommend to use backups that backup to a different device.

With backups you have two things to think of: Recovery Point Objective (RPO), that is how far in time do you want to go back, and Recovery Time Objective (RTO), that is how long may it take to recover the vm.

You can use VMware Data Recovery or one of the third party products for backup.

[ndubula]

Thank you for this detail. I am new to VMware, have taken a snapshot as per your first instruction and it completed successfully. If I weant to delete it, where do I find it and is it just select and delete, no harm? Thanks.

[RvdNieuwendijk]

To delete a snapshot you select the vm and then open the Snapshot Manager with the button in the button bar. Select the snapshot and click "Delete".

If you want to go back in time and revert to the point were you took the snapshot, you have to click on "Go to".

[ndubula]

Thank you, I am happy to have you here. Your help is highly appreciated.

[RvdNieuwendijk]

I am glad I could help you.