https://www.howtoforge.com/high-availability-storage-with-glusterfs-3.2.x-on-centos-6.3-automatic-file-replication-mirror-across-two-storage-servers
https://www.howtoforge.com/high-availability-storage-with-glusterfs-3.2.x-on-centos-6.3-automatic-file-replication-mirror-across-two-storage-servers