If there is a direct network connection (layer 2) between the old cluster and the new cluster, with less than 1ms latency, then you could put a host into maintenance mode, relocate it and simply turn it on again at the new location. So you could move one host after the other. But the networks must exist at both locations, the communication between all hosts and other components (vCenter) must still be possible and the latency in the vSAN network must not be higher than 1ms.
If this is not possible because the new location is in a different street/city and there is no direct L2 connection between the sites, then I would shut down all VMs, put the servers into maintenance mode, turn them off and move all servers at once.
there should be Layer 2 connection . but I don't know does latency is under 1ms.
thanks for replay.
Since you're using vSAN 6.0/6.1/6.2 (vSphere 6.0x), you'll need to make sure you've got multicast connectivity as well.
Mine one host has a hardware failure he cannot boot, so hole operation is stopped. VSAN fork ,HA did the job of migration vm to other hosts. Can I just that host disconnect ? there is no need for another step. host is power off..