When multiple users or services use the same ApsaraDB for HBase cluster, the resource preemption occurs. The reads and writes of some important online services may be adversely affected by multiple concurrent reads and writes of offline services. ApsaraDB for HBase provides the Group feature to isolate resources for multiple tenants. To isolate the resources, you can assign RegionServers to different groups and host different tables in the group. The preceding figure shows that RegionServer1 and RegionServer2 are assigned to Group1 and RegionServer3 and RegionServer4 are assigned to Group2. Table1 and Table2 are also moved to Group1. In this case, all regions of Table1 and Table2 are distributed to RegionServer1 and RegionServer2 in Group1. All regions of Table3 and Table4 are distributed to RegionServer3 and RegionServer4 in Group2. Therefore, the requests to Table1 and Table2 are sent to RegionServer1 and RegionServer2. The requests to Table3 and Table4 are sent to RegionServer3 and RegionServer4. This mechanism helps you to isolate resources.

ApsaraDB for HBase Performance-enhanced Edition allows you to manage groups in the Cluster Management System.

You can view the information of all groups of the current cluster on the home page. If you have not created any group, the system provides a default group. All RegionServers and tables belong to the default group.

Create a group

On the Groups page, choose More > Create Group. After a new group is created, the numbers of servers and tables in this group are both 0. You must move servers and tables to this group.

Delete a group

Click Delete in the Actions column on the home page of the Cluster Management System to delete the corresponding group. Note: Before you delete a group, you must delete all tables and servers in the group. Otherwise, the deletion fails.

Move a RegionServer to a group

By default, all RegionServers belong to the default group. You must move the servers to the required group before you use them. Follow these steps: 1. On the home page of Cluster Management System, select the RegionServer in the Cluster servers table and click Move.

2. In the dialog box that appears, select the target group from the drop-down list and click OK.

Notes:1. If you move a table to a group that does not contain any RegionServer, the region of the table cannot be accessed because no online server is available.2. We recommend that you distribute at least two RegionServers to a group. If one of the RegionServers stops responding, you can access another server in the same group. If the only RegionServer in a group stops responding, all tables in this group cannot be accessed.3. After you move a RegionServer to a group, the online regions on this RegionServer are shared among all other RegionServers in the group and requests are evenly distributed to these regions. This ensures the server load balancing.

Configure the group for a namespace

If you do not configure a group for a namespace, all tables that you create belong to the default group. Regions are only available in the default group. If you do not want to group tables every time you create tables, you can specify a group for the namespace. All tables created in this namespace can be added to the same group. 1. On the Namespaces page in the Cluster Management System, click Bind Group in the Actions column of the corresponding namespace.
2. In the dialog box that appears, select the target group from the drop-down list and click OK. Notes:1. If you modify the group information of the namespace, the groups of the existing tables in this namespace are not changed.2. If you have bound a group to the namespace, all tables created in this namespace also belong to this group. You can move the tables to other groups.

Configure a group for tables

Follow the steps to change the group of a table: 1. On the User tables page of Cluster Management System, select the table and click Move.

2. In the dialog box that appears, select the target group from the drop-down list and click OK. Notes:You must move tables to the group that contains RegionServers. Otherwise, these tables cannot be found in existing regions.