Currently I have 2 physical servers and installed esxi on both and managing via vCenter. Both server resources are identical, HDD: 600GB, Ram:256GB. (Total: 1.2TB hdd, 512GB ram)
So currently Server 1 is used as production and running, on the other hand Server 2 is used as fail-over, vMotion purpose. So when VM is Server 1 goes down, it gets automatically migrated into VM in Server 2.
The question is that from Server 1, can I allocate more than 600GB of HDD space into vm when it exceeds the capacity of physical HDD in Server 1? Which meanse can 2 servers' resouces be shared so that I can use not only 600GB but 1.2TB of HDD. Also same for ram allocation.
Is it limited to Server 1's physical capcity of can they be shared?
See my responses here for vMotion discussion and how that's not what you're needing in this case. As far as the disk allocation, no, if these VMs are stored on local storage on individual hosts, while you can *tell* it it can use more than the available space, you can't actually use more than what the datastore has available. And, no, you cannot somehow share the local disk in your second ESXi host with VMs running on the first host.