16.4. Attaching a Tier to a Volume (Deprecated) Warning Tiering is considered deprecated as of Red Hat Gluster Storage 3.5. Red Hat no longer recommends its use, and does not support tiering in new deployments and existing deployments that upgrade to Red Hat Gluster Storage 3.5.3. By default, tiering is not enabled on gluster volumes. An existing volume can be modified via a CLI command to have a hot tier . You must enable a volume by performing an attach tier operation. The attach command will declare an existing volume as cold tier and creates a new hot tier volume which is appended to it. Together, the combination is a single tiered volume. It is highly recommended to provision your storage liberally and generously before attaching a tier. You create a normal volume and then attach bricks to it, which are the hot tier : Attach the tier to the volume by executing the following command: # gluster volume tier VOLNAME attach [replica COUNT] NEW-BRICK... For example, Run gluster volume info command to optionally display the volume information. The command output displays information similar to the following: The tier start command is triggered automatically after the tier has been attached. In some cases, if the tier process has not started you must start it manually using the gluster volume tier VOLNAME start force command. 16.4.1. Attaching a Tier to a Geo-replicated Volume (Deprecated) Warning Tiering is considered deprecated as of Red Hat Gluster Storage 3.5. Red Hat no longer recommends its use, and does not support tiering in new deployments and existing deployments that upgrade to Red Hat Gluster Storage 3.5.3. You can attach a tier volume to the master volume of the geo-replication session for better performance. Important A crash has been observed in the Slave mounts when performance.quick-read option is enabled and geo-replicated from a tiered master volume. If the master volume is a tiered volume, you must disable the performance.quick-read option in the Slave Volume using the following command: Stop geo-replication between the master and slave, using the following command: # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL stop For example: Attach the tier to the volume using the following command: # gluster volume tier VOLNAME attach [replica COUNT ] NEW-BRICK... For example, to create a distributed-replicated tier volume with replica count two: Restart the geo-replication sessions, using the following command: # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL start For example Verify whether geo-replication session has started with tier's bricks, using the following command: # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL status For example,

Commands:
gluster volume tier test-volume attach replica 3 server1:/rhgs/brick5/b1 server2:/rhgs/brick6/b2 server1:/rhgs/brick7/b3 server2:/rhgs/brick8/b4
gluster volume info test-volume Volume Name: test-volume Type: Tier Status: Started Number of Bricks: 8 Transport-type: tcp Hot Tier : Hot Tier Type : Distributed-Replicate Number of Bricks: 2 x 2 = 4 Brick1: server1:/rhgs/brick5/b1 Brick2: server2:/rhgs/brick6/b2 Brick3: server1:/rhgs/brick7/b3 Brick4: server2:/rhgs/brick8/b4 Cold Tier: Cold Tier Type : Distributed-Replicate Number of Bricks: 2 x 2 = 4 Brick5: server1:/rhgs/brick1/b5 Brick6: server2:/rhgs/brick2/b6 Brick7: server1:/rhgs/brick3/b7 Brick8: server2:/rhgs/brick4/b8 Options Reconfigured: cluster.watermark-low: 70 cluster.watermark-hi: 90 cluster.tier-demote-frequency: 45 cluster.tier-mode: cache features.ctr-enabled: on performance.readdir-ahead: on
gluster volume set Slavevol performance.quick-read off
gluster volume geo-replication Volume1 example.com::slave-vol stop
gluster volume tier test-volume attach replica 3 server1:/rhgs/brick1/b1 server2:/rhgs/brick2/b2 server1:/rhgs/brick3/b3 server2:/rhgs/brick4/b4
gluster volume geo-replication Volume1 example.com::slave-vol start
gluster volume geo-replication Volume1 example.com::slave-vol status