This topic describes useful concepts for the management of tenants and resources.
OceanBase Database is a multi-tenant distributed database. You can create multiple independent tenants in the same cluster, and each tenant is an independent database service. You can specify the required hardware resources and create database service objects, such as accounts, tables, and storage procedures. Resource pool contains the hardware resources for a tenant. It is composed of multiple resource units, which refer to CPUs, memories, disks, and other hardware resources allocated.
Before you create a tenant, you must specify the range of resource that the tenant uses. Resource pools and resource units can meet the needs of resource isolation and load balancing.
Resource unit
Resource units refer to physical resources such as CPUs, memory, and disks. Resource units are resource containers in OceanBase Database. Resource units automatically perform load balancing in the cluster. A resource unit is placed on a server with sufficient resources to accommodate it. Before you delete a cluster server, you must migrate the resource unit on the server to another server. If the resources of other servers in the cluster are insufficient to accommodate the resource unit to be migrated, you cannot delete the server.
Resource unit configuration
Resource unit configuration describes the configuration information of resource units. Each resource unit configuration describes the CPU, memory, disk, and IOPS of one specification. You can change the resource configurations to dynamically adjust the computing resources of resource units and the resources of corresponding tenants.
Resource pool
A resource pool consists of several resource units that share the same resource unit configurations. A resource pool belongs to only one tenant. One tenant has one or several resource pools, which contain all physical resources available to the tenant. One tenant has at most one resource unit on the same server.
Resource unit balance
OceanBase Database balances the resource units of the same tenant among servers in the cluster. If a tenant has several resource units in one or more resource pools, the following balance strategies apply to units in each zone:
OceanBase evenly distribute several resource units of the same tenant to different servers.
When the server storage usage exceeds the specified threshold, OceanBase exchanges or migrates resource units to decrease the storage usage.
Resource units can be exchanged or migrated based on the CPU and memory specifications of the resource units, to reduce the average CPU and memory usage.