Some nodes in a RHEL 6 Resilient Storage cluster block or hang indefinitely when shutting down or rebooting the entire cluster at the same time

Issue

• 4 node cluster running clvmd and gfs2, seems to have some timing issue. Sometimes when rebooting all cluster nodes, a node will hang during shutdown with this message "Stopping block device availability: Deactivating block devices"
• When I reboot my three-node cluster at the same time for maintenance, one of the nodes becomes stuck and doesn't boot until the other nodes come back up.
• Some nodes in my cluster hang when all of them are being shut down around the same time