Chapter 9. Managing GFS
99
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
inherit_jdata
flag on a directory. All files created in the directory
or any of its subdirectories will have the
jdata
flag assigned automatically. Any data written to the
files will be journaled.
gfs_tool setflag inherit_jdata /gfs1/data/
This example shows setting the
jdata
flag on a file. The file must be zero size. Any data written to
the file will be journaled.
gfs_tool setflag jdata /gfs1/datafile
9.9. Configuring
atime
Updates
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 signifi-
cant 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
9.9.1. Mount with
noatime
A standard Linux mount option,
noatime
, may be specified when the file system is mounted, which
disables
atime
updates on that file system.
9.9.1.1. Usage
mount -t gfs
BlockDevice MountPoint
-o noatime
BlockDevice
Specifies the block device where the GFS file system resides.
Содержание GFS 5.2.1 -
Страница 1: ...Red Hat GFS 5 2 1 Administrator s Guide...
Страница 8: ......
Страница 14: ...vi Introduction...
Страница 24: ...10 Chapter 1 GFS Overview...
Страница 36: ...22 Chapter 4 Initial Configuration...
Страница 84: ...70 Chapter 6 Creating the Cluster Configuration System Files...
Страница 96: ...82 Chapter 8 Using Clustering and Locking Systems...
Страница 126: ...112 Chapter 10 Using the Fencing System...
Страница 132: ...118 Chapter 11 Using GNBD...
Страница 144: ...130 Appendix A Upgrading GFS...
Страница 184: ...170 Appendix B Basic GFS Examples...
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