Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Mail Systems
Eclipse Documentation

How To Guides
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Problem Solutions
Privacy Policy




4.9.2. Tune GFS atime Quantum

When atime updates are enabled, GFS (by default) only updates them once an hour. The time quantum is a tunable parameter that can be adjusted using the gfs_tool command.

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, atime_quantum, then atime updates are written more frequently. Increasing the frequency of atime updates may cause performance degradation in clusters with heavy work loads.

By using the gettune flag of the gfs_tool command, all current tunable parameters including atime_quantum (default is 3600 seconds) are displayed.

The gfs_tool settune command is used to change the atime_quantum parameter value. It must be set on each node and each time the file system is mounted. (The setting is not persistent across unmounts.)


Displaying Tunable Parameters

gfs_tool gettune MountPoint

Specifies the directory where the GFS file system is mounted.

Changing the atime_quantum Parameter Value

gfs_tool settune MountPoint atime_quantum Seconds

Specifies the directory where the GFS file system is mounted.


Specifies the update period in seconds.


In this example, all GFS tunable parameters for the file system on the mount point /gfs1 are displayed.

gfs_tool gettune /gfs1

In this example, the atime update period is set to once a day (86,400 seconds) for the GFS file system on mount point /gfs1.

gfs_tool settune /gfs1 atime_quantum 86400

  Published under the terms of the Open Publication License Design by Interspire