Snapshots questions

[Guv]

I have a VM which has an application installed and we want to install some updates on the VM, but want a backup of the server just in case we want to roll back.  So i thought i would do a snapshot of the VM, so that if there are any issues we can roll back.  But I have few questions regarding snapshots.   First of all how much space will the snapshot take as the VM has two disks, one has 30 gb and the second disk has 140 gb, and the memory it uses is 2GB.  I have about 20GB disk space left on datastore.

Also will the snapshot affect the performance of the VM, as we may need the snapshot for more than a week.

Any advise on snapshots.

[MauroBonder]

The volume of data that is stored in the delta snaphot will depend on the amount of data that is generated / used in the VM after snapshot is set.

If you have 2GB forecast of apply Patch in the VM, you know you will grow more than 2GB, allow reasonable considering this scenario, but the snapshot should be just a state of security and that assmi validated, should be removed.

also read kb.vmware.com/kb/1025279

good luck