Crate a second datastore to store new VM's

Hi!

I've this issue:

on my ESXi server there are N.2 physical SAS disk each of 140 GB in size.

The first disk is that I've used to initially install ESXi 5 server and is that on wich there is the datastore that hosts all my VMs.

But the first disk is now full and there is no space for other VMs.

The question is:

is there any way to use the second physical SAS disk to create another datastore and use it to add new VMs so that I can use it on the same vSwitch as they was on the first datastore and first disk?

And if yes, because the server in in a production environment may I add the new datastore on the second physical disk without stop the server and without affect in any way the actually working VMs?

Thanks in advance.