Configuring Atime Updates; Mount With Noatime - Red Hat GLOBAL FILE SYSTEM 4.5 Manual

Directory
Specifies the directory where the flag is set or cleared.
File
Specifies the zero-length file where the flag is set or cleared.
Examples
This example shows setting the
directory or any of its subdirectories will have the
written to the files will be journaled.
gfs_tool setflag inherit_jdata /gfs1/data/
This example shows setting the
to the file will be journaled.
gfs_tool setflag jdata /gfs1/datafile
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
atime
every time a file is read, its inode needs to be updated.
Because few applications use the information provided by
significant 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 quantum
atime
inherit_jdata
flag on a file. The file must be zero size. Any data written
jdata
Updates
atime
updating are available:
atime
flag on a directory. All files created in the
flag assigned automatically. Any data
jdata
, those updates can require a
atime
updates.
atime
Examples
35