Managing Directory Quotas

Directory quotas allow you to set limits on disk space used by directories or the volume. Storage administrators can control the disk space utilization at the directory or the volume level, or both. This is particularly useful in cloud deployments to facilitate the use of utility billing models.

Enabling Quotas

You must enable directory quotas to set disk limits.

Enable quotas on a volume using the following command:

`# gluster volume quota VOLNAME enable `

For example, to enable quota on test-volume:

# gluster volume quota test-volume enable
volume quota : success

Important

  • Do not enable quota using the volume-set command. This option is no longer supported.

  • Do not enable quota while quota-remove-xattr.sh is still running.

Setting Limits

Note

  • Before setting quota limits on any directory, ensure that there is at least one brick available per replica set.

    To see the current status of bricks of a volume, run the following command:

    # gluster volume status VOLNAME status

  • If the GlusterFS volume is mounted at /mntglusterfs and you want to perform a certain function pertaining to Quota on /mntglusterfs/dir, then the path to be provided in any corresponding command should be /dir, where /dir is the absolute path relative to the GlusterFS volume mount point.

A Hard Limit is the maximum disk space you can utilize on a volume or directory.

Set the hard limit for a directory in the volume with the following command, specifying the hard limit size in MB, GB, TB or PB:

`# gluster volume quota VOLNAME limit-usage path hard_limit `

For example:

  • To set a hard limit of 100GB on /dir:

    # gluster volume quota VOLNAME limit-usage /dir 100GB

  • To set a hard limit of 1TB for the volume:

    # gluster volume quota VOLNAME limit-usage / 1TB

A Soft Limit is an attribute of a directory that is specified as a percentage of the hard limit. When disk usage reaches the soft limit of a given directory, the system begins to log this information in the logs of the brick on which data is written. The brick logs can be fount at:

/var/log/glusterfs/bricks/<path-to-brick.log>

By default, the soft limit is 80% of the hard limit.

Set the soft limit for a volume with the following command, specifying the soft limit size as a percentage of the hard limit:

# gluster volume quota VOLNAME limit-usage path hard_limit soft_limit

For example:

  • To set the soft limit to 76% of the hard limit on /dir:

    # gluster volume quota VOLNAME limit-usage /dir 100GB 76%

  • To set the soft limit to 68% of the hard limit on the volume:

    # gluster volume quota VOLNAME limit-usage / 1TB 68%

Note

When setting the soft limit, ensure you retain the hard limit value previously created.

Setting the Default Soft Limit

The default soft limit is an attribute of the volume that is specified as a percentage. The default soft limit for any volume is 80%.

When you do not specify the soft limit along with the hard limit, the default soft limit is applied to the directory or volume.

Configure the default soft limit value using the following command:

# gluster volume quota VOLNAME default-soft-limit soft_limit

For example, to set the default soft limit to 90% on test-volume run the following command:

# gluster volume quota test-volume default-soft-limit 90%
volume quota : success

Ensure that the value is set using the following command:

# gluster volume quota test-volume list

Note

If you change the soft limit at the directory level and then change the volume’s default soft limit, the directory-level soft limit previously configured will remain the same.

Displaying Quota Limit Information

You can display quota limit information on all of the directories on which a limit is set.

To display quota limit information on all of the directories on which a limit is set, use the following command:

# gluster volume quota VOLNAME list

For example, to view the quota limits set on test-volume:

# gluster volume quota test-volume list
Path       Hard-limit  Soft-limit   Used    Available

/ 50GB 75% 0Bytes 50.0GB /dir 10GB 75% 0Bytes 10.0GB /dir/dir2 20GB 90% 0Bytes 20.0GB

To display disk limit information on a particular directory on which
limit is set, use the following command:

`# gluster volume quota VOLNAME list /<directory_name>`

For example, to view limits set on /dir directory of the volume
/test-volume :

-------------------------------------------------
# gluster volume quota test-volume list /dir
Path  Hard-limit   Soft-limit   Used   Available
-------------------------------------------------
/dir   10.0GB          75%       0Bytes  10.0GB
-------------------------------------------------

To display disk limit information on multiple directories on which a
limit is set, using the following command:

`# gluster volume quota VOLNAME list /<directory_name1> /<directory_name2>`

For example, to view quota limits set on directories /dir and /dir/dir2
of volume test-volume :

gluster volume quota test-volume list /dir /dir/dir2

Path Hard-limit Soft-limit Used Available

/dir       10.0GB        75%        0Bytes     10.0GB
/dir/dir2  20.0GB        90%        0Bytes     20.0GB

Displaying Quota Limit Information Using the df Utility

To report the disk usage using the df utility, taking quota limits into consideration, run the following command:

# gluster volume set VOLNAME quota-deem-statfs on

In this case, the total disk space of the directory is taken as the quota hard limit set on the directory of the volume.

The following example displays the disk usage when quota-deem-statfs is off:

# gluster volume set test-volume features.quota-deem-statfs off
volume set: success
# gluster volume quota test-volume list
Path        Hard-limit    Soft-limit     Used     Available
-----------------------------------------------------------
/              300.0GB        90%        11.5GB     288.5GB
/John/Downloads 77.0GB        75%        11.5GB     65.5GB

Disk usage for volume test-volume as seen on client1:

# df -hT /home
Filesystem           Type            Size  Used Avail Use% Mounted on
server1:/test-volume fuse.glusterfs  400G   12G  389G   3% /home

The following example displays the disk usage when quota-deem-statfs is on:

# gluster volume set test-volume features.quota-deem-statfs on
volume set: success
# gluster vol quota test-volume list
Path        Hard-limit    Soft-limit     Used     Available
-----------------------------------------------------------
/              300.0GB        90%        11.5GB     288.5GB
/John/Downloads 77.0GB        75%        11.5GB     65.5GB

Disk usage for volume test-volume as seen on client1:

# df -hT /home
Filesystem            Type            Size  Used Avail Use% Mounted on
server1:/test-volume  fuse.glusterfs  300G   12G  289G   4% /home

The quota-deem-statfs option when set to on, allows the administrator to make the user view the total disk space available on the directory as the hard limit set on it.

Setting Timeout

There are two types of timeouts that you can configure for a volume quota:

  • Soft timeout is the frequency at which the quota server-side translator checks the volume usage when the usage is below the soft limit. The soft timeout is in effect when the disk usage is less than the soft limit.

    To set the soft timeout, use the following command:

    # gluster volume quota VOLNAME soft-timeout time

    Note

    The default soft timeout is 60 seconds.

    For example, to set the soft timeout on test-volume to 1 minute:

    # gluster volume quota test-volume soft-timeout 1min
volume quota : success

  • Hard timeout is the frequency at which the quota server-side translator checks the volume usage when the usage is above the soft limit. The hard timeout is in effect when the disk usage is between the soft limit and the hard limit.

    To set the hard timeout, use the following command:

    # gluster volume quota VOLNAME hard-timeout time

    Note

    The default hard timeout is 5 seconds.

    For example, to set the hard timeout for 30 seconds:

    # gluster volume quota test-volume hard-timeout 30s
volume quota : success

    Note

    As the margin of error for disk usage is proportional to the workload of the applications running on the volume, ensure that you set the hard-timeout and soft-timeout taking the workload into account.

Setting Alert Time

Alert time is the frequency at which you want your usage information to be logged after you reach the soft limit.

To set the alert time, use the following command:

# gluster volume quota VOLNAME alert-time time

Note

The default alert-time is 1 week.

For example, to set the alert time to 1 day:

# gluster volume quota test-volume alert-time 1d
volume quota : success

Removing Disk Limits

You can remove disk limit usage settings on a given directory, if quota set is not required.

Remove disk limit usage set on a particular directory using the following command:

# gluster volume quota VOLNAME remove /<directory-name>

For example, to remove the disk limit usage on /data directory of test-volume:

# gluster volume quota test-volume remove /data
volume quota : success

For example, to remove quota from volume:

# gluster vol quota test-volume remove /
volume quota : success

Note

Removing quota limit from the volume ("/" in the above example) does not impact quota limit usage on directories.

Disabling Quotas

You can disable directory quotas using the following command:

`# gluster volume quota VOLNAME disable `

For example, to disable directory quotas on test-volume:

# gluster volume quota test-volume disable
Disabling quota will delete all the quota configuration. Do you want to continue? (y/n) y
volume quota : success

Note

When you disable quotas on GlusterFS 3.1.1 and earlier, all previously configured limits are removed from the volume by a cleanup process. If you re-enable quotas while the cleanup process is still in progress, the extended attributes that enable quotas may be removed by the cleanup process. This has negative effects on quota accounting.

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