Shrinking Volume

Shrinking Volumes

You can shrink volumes, as needed, while the cluster is online and available. For example, you might need to remove a brick that has become inaccessible in a distributed volume due to hardware or network failure.

Note

Data residing on the brick that you are removing will no longer be accessible at the Gluster mount point. Note however that only the configuration information is removed - you can continue to access the data directly from the brick, as necessary.

When shrinking distributed replicated and distributed dispersed volumes, you need to remove a number of bricks that is a multiple of the replica or stripe count. For example, to shrink a distributed replicate volume with a replica count of 2, you need to remove bricks in multiples of 2 (such as 4, 6, 8, etc.). In addition, the bricks you are trying to remove must be from the same sub-volume (the same replica or disperse set).

Running remove-brick with the start option will automatically trigger a rebalance operation to migrate data from the removed-bricks to the rest of the volume.

To shrink a volume

Remove the brick using the following command:

# gluster volume remove-brick <VOLNAME> <BRICKNAME> start

For example, to remove server2:/exp2:
```
# gluster volume remove-brick test-volume server2:/exp2 start
volume remove-brick start: success
```

View the status of the remove brick operation using the following command:

# gluster volume remove-brick <VOLNAME> <BRICKNAME> status

For example, to view the status of remove brick operation on server2:/exp2 brick:

# gluster volume remove-brick test-volume server2:/exp2 status
                                Node  Rebalanced-files  size  scanned       status
                           ---------  ----------------  ----  -------  -----------
617c923e-6450-4065-8e33-865e28d9428f               34   340      162   in progress

Once the status displays "completed", commit the remove-brick operation

# gluster volume remove-brick <VOLNAME> <BRICKNAME> commit

In this example:

# gluster volume remove-brick test-volume server2:/exp2 commit
Removing brick(s) can result in data loss. Do you want to Continue? (y/n) y
volume remove-brick commit: success
Check the removed bricks to ensure all files are migrated.
If files with data are found on the brick path, copy them via a gluster mount point before re-purposing the removed brick.

Check the volume information using the following command:

# gluster volume info

The command displays information similar to the following:

# gluster volume info
Volume Name: test-volume
Type: Distribute
Status: Started
Number of Bricks: 3
Bricks:
Brick1: server1:/exp1
Brick3: server3:/exp3
Brick4: server4:/exp4