1.check the log about the vm business hang .
Analysis the RedHat host log and find that the host has an IO response stuck in 2018-01-27 12:51.
2.20:51:41 The host multipath reported a path interruption (checked that each host had only one path). The available path of the system became 0. Because the host did not have a path, the KVM virtualization service was interrupted.
3.The KVM VM is stuck because Redhat has a known bug (KVM will hang automatically after the back-end storage is restarted and cannot be automatically restored). The KVM version needs to be upgraded and the multipathing solution must be adjusted.
