Before setting up Red Hat GFS, make sure that you have noted the key characteristics of the GFS nodes (refer to Section 1.5, “Before Setting Up GFS”) and have loaded the GFS modules into each GFS node.Also, make sure that the clocks on the GFS nodes are synchronized. It is recommended that you use the Network Time Protocol (NTP) software provided with your Red Hat Enterprise Linux distribution. In addition, if you are using GNBD multipath, make sure that you understand GNBD multipath considerations. For information on GNBD multipath, see the document Using GNBD with Global Filesystem.
The system clocks in GFS nodes must be within a few minutes of each other to prevent unnecessary inode time-stamp updating. Unnecessary inode time-stamp updating severely impacts cluster performance.