Quantum - Red Hat GFS 6.1 Administrator's Manual

Chapter 5. Managing GFS
5.9.1.1. Usage
BlockDevice MountPoint
mount
-t gfs
BlockDevice
Specifies the block device where the GFS file system resides.
MountPoint
Specifies the directory where the GFS file system should be mounted.
5.9.1.2. Example
In this example, the GFS file system resides on the
directory with atime updates turned off.
/gfs1
mount -t gfs /dev/vg01/lvol0 /gfs1 -o noatime
5.9.2. Tune GFS
When updates are enabled, GFS (by default) only updates them once an hour. The
atime
time quantum is a tunable parameter that can be adjusted using the
Each GFS node updates the access time based on the difference between its system time
and the time recorded in the inode. It is required that system clocks of all GFS nodes in a
cluster be synchronized. If a node's system time is out of synchronization by a significant
fraction of the tunable parameter,
frequently. Increasing the frequency of
in clusters with heavy work loads.
By using the
gettune
including
atime_quantum
The
gfs_tool
settune
value. It must be set on each node and each time the file system is mounted. (The set-
ting is not persistent across unmounts.)
5.9.2.1. Usage
Displaying Tunable Parameters
gfs_tool
gettune

Quantum

atime
atime_quantum
flag of the
gfs_tool
(default is 3600 seconds) are displayed.
command is used to change the
MountPoint
-o noatime
/dev/vg01/lvol0
, then
updates may cause performance degradation
atime
command, all current tunable parameters
and is mounted on
gfs_tool
updates are written more
atime
atime_quantum
51
command.
parameter