5.9. Creating Dispersed Volumes
Figure 5.7. Illustration of a Dispersed Volume
n = k + m. Here
nis the total number of bricks, we would require any
kbricks out of
nbricks for recovery. In other words, we can tolerate failure up to any
mbricks. With this release, the following configurations are supported:
- 6 bricks with redundancy level 2 (4 + 2)
- 10 bricks with redundancy level 2 (8 + 2)
- 11 bricks with redundancy level 3 (8 + 3)
- 12 bricks with redundancy level 4 (8 + 4)
- 20 bricks with redundancy level 4 (16 + 4)
gluster volume createto create different types of volumes, and
gluster volume infoto verify successful volume creation.
- Create a trusted storage pool as described in Section 4.1, “Adding Servers to the Trusted Storage Pool”.
- Understand how to start and stop volumes, as described in Section 5.11, “Starting Volumes”.
- Run the
gluster volume createcommand to create the dispersed volume.The syntax is
# gluster volume create NEW-VOLNAME [disperse-data COUNT] [redundancy COUNT] [transport tcp | rdma | tcp,rdma] NEW-BRICK...The number of bricks required to create a disperse volume is the sum of
countoption specifies the number of bricks that is part of the dispersed volume, excluding the count of the redundant bricks. For example, if the total number of bricks is 6 and
redundancy-countis specified as 2, then the disperse-data count is 4 (6 - 2 = 4). If the
disperse-data countoption is not specified, and only the
redundancy countoption is specified, then the
disperse-data countis computed automatically by deducting the redundancy count from the specified total number of bricks.Redundancy determines how many bricks can be lost without interrupting the operation of the volume. If
redundancy countis not specified, based on the configuration it is computed automatically to the optimal value and a warning message is displayed.The default value for transport is
tcp. Other options can be passed such as
auth.reject. See Section 5.3, “About Encrypted Disk” for a full list of parameters.
Example 5.11. Dispersed Volume with Six Storage Servers
# gluster volume create test-volume disperse-data 4 redundancy 2 transport tcp server1:/rhgs1/brick1 server2:/rhgs2/brick2 server3:/rhgs3/brick3 server4:/rhgs4/brick4 server5:/rhgs5/brick5 server6:/rhgs6/brick6 Creation of test-volume has been successful Please start the volume to access data.
# gluster volume start VOLNAMEto start the volume.
# gluster volume start test-volume Starting test-volume has been successful
open-behindvolume option is enabled by default. If you are accessing the dispersed volume using the SMB protocol, you must disable the
open-behindvolume option to avoid performance bottleneck on large file workload. Run the following command to disable
# gluster volume set VOLNAME open-behind offFor information on
open-behindvolume option, see Section 11.1, “Configuring Volume Options”
gluster volume infocommand to optionally display the volume information.