Red Hat GFS 5.2.1 -, Administrator'S Manual

Page: 101 / 192

Chapter 9. Managing GFS 87
Option Description
ignore_local_fs
Caution: This option should not be used
when GFS file systems are shared.
Forces GFS to treat the file system as a multihost file
system. By default, using LOCK_NOLOCK
automatically turns on the
localcaching
and
localflocks
flags.
localcaching
Caution:
This option should not be used
when GFS file systems are shared.
Tells GFS that it is running as a local file system. GFS
can then turn on selected optimization capabilities
that are not available when running in cluster mode.
The
localcaching
flag is automatically turned on
by LOCK_NOLOCK.
localflocks
Caution: This option should not be used
when GFS file systems are shared.
Tells GFS to let the VFS (virtual file system) layer do
all flock and fcntl. The
localflocks
flag is
automatically turned on by LOCK_NOLOCK.
Table 9-2. GFS-Specific Mount Options
9.3. Unmounting a File System
The GFS file system can be unmounted the same way as any Linux file system.
Note
The
umount
command is a Linux system command. Information about this command can be found in
the Linux
umount
command man pages.
9.3.1. Usage
umount MountPoint
MountPoint
Specifies the directory where the GFS file system should be mounted.
9.4. GFS Quota Management
File system quotas are used to limit the amount of file-system space a user or group can use. A user or
group does not have a quota limit until one is set. GFS keeps track of the space used by each user and
group even when there are no limits in place. GFS updates quota information in a transactional way
so system crashes do not require quota usages to be reconstructed.
To prevent a performance slowdown, a GFS node synchronizes updates to the quota file only pe-
riodically. The "fuzzy" quota accounting can allow users or groups to slightly exceed the set limit.
To minimize this, GFS dynamically reduces the synchronization period as a "hard" quota limit is
approached.
GFS uses its
gfs_quota
command to manage quotas. Other Linux quota facilities cannot be used
with GFS.