Synchronizing Quotas; Synchronizing Quotas; Performance - Red Hat ENTERPRISE LINUX 5 - GLOBAL FILE SYSTEM Manual

Chapter 3. Managing GFS
Space allocated to GFS's hidden files can be left out of displayed values for the root UID and GID
by adding the -d option to the command line. This is useful when trying to match the numbers from
gfs_quota with the results of a du command.
Examples
This example displays quota information for all users and groups that have a limit set or are using any
disk space on file system /gfs.
[root@ask-07 ~]# gfs_quota list -f /gfs
user root: limit: 0.0
user moe: limit: 1024.0
group root: limit: 0.0
group stooges: limit: 0.0
This example displays quota information in sectors for group users on file system /gfs.
[root@ask-07 ~]# gfs_quota get -g users -f /gfs -s
group users: limit: 0

3.6.3. Synchronizing Quotas

GFS stores all quota information in its own internal file on disk. A GFS node does not update this
quota file for every file system write; rather, it updates the quota file once every 60 seconds. This is
necessary to avoid contention among nodes writing to the quota file, which would cause a slowdown in

performance.

As a user or group approaches their quota limit, GFS dynamically reduces the time between its
quota-file updates to prevent the limit from being exceeded. The normal time period between quota
synchronizations is a tunable parameter, quota_quantum, and can be changed using the gfs_tool
command. By default, the time period is 60 seconds. Also, the quota_quantum parameter must
be set on each node and each time the file system is mounted. (Changes to the quota_quantum
parameter are not persistent across unmounts.)
To see the current values of the GFS tunable parameters, including quota_quantum, you can use
the gfs_tool gettune, as described in
You can use the gfs_quota sync command to synchronize the quota information from a node to the
on-disk quota file between the automatic updates performed by GFS.
Usage
Synchronizing Quota Information
gfs_quota sync -f MountPoint
MountPoint
Specifies the GFS file system to which the actions apply.
Tuning the Time Between Synchronizations
20
warn: 0.0 value: 0.2
warn: 0.0 value: 0.0
warn: 0.0 value: 0.2
warn: 0.0 value: 0.0
warn: 96 value: 0
Section 3.5, "Displaying GFS Tunable Parameters".