Libro sobre Proxmox maestria
Chapter 3
LAN Switch node 03 node 02 node 04 node 01 vm21 vm22 vm31 vm32 vm 1 vm2 vm 11 vm 12 vm 10 vm30 vm40 vm 20
In the previous overly simplified diagram, there are four Proxmox nodes with 10 virtual machines on each. If node 01 needs to reboot, all the 10 virtual machines have to be stopped, the node needs to be rebooted, and then all the virtual machines must be powered up. If node 01 needs to be taken offline for hardware upgrade, then all virtual machines need to be stopped and we have to manually migrate each virtual machine to a different node. If node 01 fails completely, then all these 10 virtual machines will be inaccessible till node 01 is back on again. A brave administrator might just take the hard drives out of the failed node, plug them into another Linux machine, copy the virtual machine image files directly to another node, and then power them up. But it will not work if node 01 had anything but mirror RAID in it for all the hard drives.
So clearly, a cluster setup with a local storage for virtual machines can bring chaos when migration is needed. Now, let us take a look at the following diagram where four Proxmox nodes with 40 virtual machines are stored on a shared storage system:
node 01 node 02 node 03 node 04
LAN Switch
NAS Shared Storage vm 1 vm2 vm3 vm40