Vmware Snapshot question
Posted on 2011-02-11
I only have experience using Vmware on a very basic level but have been tasked with putting together a viable backup solution for the VM's. I was in a discussion with a fellow colleague who said I can simply create snapshots and back these up. After some research, I now know this is complete false (or so I believe). So I would like some clarification.
Q. When a snapshot is created, it just creates a smaller 'reference' vmdk and a redolog (or cache file) to save all write changes occuring on the VM. This suspends the real VM to allow it to backed up if needed. This is why you can't backup a snap. So let'sa say you are patching a server - you would snap it, patch the server (the snapshot) and if it all goes well, if you deleted the snapshot, it would commit the changes to the existing VM with no downtime? If the server dies, you would just 'revert'; back to the origional VM (vmdk) and off you go?
Q. What exactly is quiesce and how does it function? From what I've read - it commits everything in memory to write to disk before creating the snap. Doing this will pause the OS (not sure how long) which this is occuring and all changes are cached until this is done. Once the memory has been committed to disk, the cache data is pushed back to the VM and the VM (OS functions) are restored.
Q. What is a good free method of taking a hotbackup of a live VM for use with a coldsite in the event the ESX host dies.