4.4.3. 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.)
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 MountPointMountPoint- Specifies the GFS file system to which the actions apply.
Tuning the Time Between Synchronizations
gfs_tool settuneMountPointquota_quantumSeconds
MountPoint- Specifies the GFS file system to which the actions apply.
Seconds- Specifies the new time period between regular quota-file synchronizations by GFS. Smaller values may increase contention and slow down performance.
Examples
This example synchronizes the quota information from the node it is run on to file system
/gfs.
gfs_quota sync -f /gfs
This example changes the default time period between regular quota-file updates to one hour (3600 seconds) for file system
/gfs on a single node.
gfs_tool settune /gfs quota_quantum 3600
