Examples; Configuring Atime; Mount With; Tune Gfs - Red Hat GFS 5.2.1 Administrator's Manual

Chapter 9. Managing GFS
Directory
Specifies the directory where the flag is set or cleared.
File
Specifies the zero-length file where the flag is set or cleared.

9.8.2. Examples

This example shows setting the
or any of its subdirectories will have the
files will be journaled.
gfs_tool setflag inherit_jdata /gfs1/data/
This example shows setting the
the file will be journaled.
gfs_tool setflag jdata /gfs1/datafile
9.9. Configuring
Each file inode and directory inode has three time stamps associated with it:
— The last time the inode status was changed
•
ctime
— The last time the file (or directory) data was modified
• mtime
— The last time the file (or directory) data was accessed
• atime
If updates are enabled as they are by default on GFS and other Linux file systems then every
atime
time a file is read, its inode needs to be updated.
Because few applications use the information provided by
cant amount of unnecessary write traffic and file-locking traffic. That traffic can degrade performance;
therefore, it may be preferable to turn off
Two methods of reducing the effects of

Mount with

• noatime

Tune GFS

• atime
9.9.1. Mount with
A standard Linux mount option,
disables updates on that file system.
atime
9.9.1.1. Usage
mount -t gfs BlockDevice MountPoint -o noatime
BlockDevice
Specifies the block device where the GFS file system resides.
inherit_jdata
flag on a file. The file must be zero size. Any data written to
jdata
Updates
atime
atime
quantum
noatime
noatime
flag on a directory. All files created in the directory
flag assigned automatically. Any data written to the
jdata
atime
updates.
atime
updating are available:
, may be specified when the file system is mounted, which
, those updates can require a signifi-
99