Best practices for using snapshots in vsphere environment

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Snapshots are good way of creating a quick recovery point in case the changes to be performed in immediate future cause VM to crash. However, there are best practices for using snapshots such as:

We should not use snapshots as backups. There should be separate backup mechanism for backup.
We should not use more than 2 or 3 snapshots in a chain.
It is not ideal to keep snapshot for more than 2-3 days. As soon as activity is over and VM is stable, snapshots should be deleted
If snapshots are used for backup process, then after backup is complete the snapshot should be deleted
We should delete snapshots before increasing VM disk space by increasing size of virtual RDM.

Refer:

https://kb.vmware.com/s/article/1025279

Disk consolidation

At least till vSphere 6.5 deleting snapshots does not automatically improves performance as the snapshot deltas are left as it is until disk consolidation is performed. Disk consolidation is very important but slow process. The most important point related to disk consolidation is that virtual machine power state cannot be changed during consolidation. Hence, if we consolidate disks when guest is powered off, it cannot be powered on. Given that disk consolidation takes considerable time, it might lead to long down-time. Hence, if there is enough free space available live consolidation can be attempted with caution notice on VM stunning as mentioned in below links.

Useful links related to disk consolidation are:

Comprehensive FAQ. Clearly lists that once process is started it cannot be stopped and power operations also cannot be done. Difference between doing this when VM is powered on vs when VM is powered off is also listed.