Red Hat GLOBAL FILE SYSTEM 5.2, Руководство пользователя

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Each file inode and directory inode has three time stamps associated with it:
•
ctime
— The last time the inode status was changed
•
mtime
— The last time the file (or directory) data was modified
•
atime
— The last time the file (or directory) data was accessed
If
atime
updates are enabled as they are by default on GFS and other Linux file systems then
every time a file is read, its inode needs to be updated.
Because few applications use the information provided by
atime
, those updates can require a
significant amount of unnecessary write traffic and file-locking traffic. That traffic can degrade
performance; therefore, it may be preferable to turn off
atime
updates.
Two methods of reducing the effects of
atime
updating are available:
• Mount with
noatime
• Tune GFS
atime
quantum
10.1. Mount with
noatime
A standard Linux mount option,
noatime
, can be specified when the file system is mounted,
which disables
atime
updates on that file system.
Usage
mount BlockDevice MountPoint -o noatime
BlockDevice
Specifies the block device where the GFS file system resides.
MountPoint
Specifies the directory where the GFS file system should be mounted.
Example
In this example, the GFS file system resides on the
/dev/vg01/lvol0
and is mounted on
directory
/gfs
with atime updates turned off.
mount /dev/vg01/lvol0 /gfs -o noatime
Chapter 3. Managing GFS
34