---
title: "通过调整 Unit Number 实现租户扩缩容 - OceanBase 数据库 V4.1.0 | OceanBase 文档中心"
description: 通过调整 Unit Number 实现租户扩缩容 租户扩容和缩容本质上是提高和降低租户的服务能力，包括计算能力和存储容量。可以通过提高单节点的服务能力达成，也可以通过增加服务节点达成。本文介绍如何通过修改 Unit Number，从而增加或减少服务节点，达到租户总服务能力的提升或降低，实现租户的扩容或缩容。 使用限制…
---
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# 通过调整 Unit Number 实现租户扩缩容

更新时间：2023-09-27 20:10:52

[编辑](https://github.com/oceanbase/oceanbase-doc/edit/V4.1.0/zh-CN/600.manage/200.tenant-management/600.common-tenant-operations/800.tenant-scale-in-and-out/300.adjust-unit-number.md)  

租户扩容和缩容本质上是提高和降低租户的服务能力，包括计算能力和存储容量。可以通过提高单节点的服务能力达成，也可以通过增加服务节点达成。本文介绍如何通过修改 Unit Number，从而增加或减少服务节点，达到租户总服务能力的提升或降低，实现租户的扩容或缩容。

## 使用限制

当前版本暂不支持调小 Unit Number。

## 前提条件

在进行租户的扩容和缩容操作前，需要进行以下操作：

- 由于空闲的资源池会被计算为占用的资源，故在扩容前，如果有租户被删除，建议与租户对应的资源池也一并删除，以便释放资源。

  删除资源池的相关操作，参见 [删除资源池](https://www.oceanbase.com/docs/common-oceanbase-database-cn-10000000001697250)。
 - 进行租户缩容前，建议进行一轮转储以便释放租户正在使用的内存。

  手动触发转储的相关操作，参见 [手动触发转储](https://www.oceanbase.com/docs/common-oceanbase-database-cn-10000000001701236)。
 - 查看集群中资源的分配情况，了解集群中资源的使用情况。

  查看集群节点的资源总量和分配状态的相关操作，参见 [查看集群的资源信息](https://www.oceanbase.com/docs/common-oceanbase-database-cn-10000000001701028)。

## 操作步骤

下面以调整租户 `mq_t1` 的 Unit Number 为例来介绍操作方法。

1. 使用 root 用户登录到集群的 sys 租户。

   ```shell
   obclient -h172.30.xxx.xxx -P2883 -uroot@sys#obdemo -pxxxx -A

   ```
 2. 进入 `oceanbase` 数据库。

   ```shell
   obclient>use oceanbase;

   ```
 3. 查看租户 `mq_t1` 信息，获取其 `TENANT_ID`。

   ```shell
    obclient> SELECT * FROM oceanbase.DBA_OB_TENANTS WHERE TENANT_NAME = 'mq_t1';
    +-----------+-------------+-------------+----------------------------+----------------------------+----------------------------------------+------------------------------------------------------------------+-------------------+--------------------+--------+---------------+--------+-------------+-------------------+------------------+---------------------+---------------------+---------------------+---------------------+--------------+----------------------------+
    | TENANT_ID | TENANT_NAME | TENANT_TYPE | CREATE_TIME                | MODIFY_TIME                | PRIMARY_ZONE                           | LOCALITY                                                         | PREVIOUS_LOCALITY | COMPATIBILITY_MODE | STATUS | IN_RECYCLEBIN | LOCKED | TENANT_ROLE | SWITCHOVER_STATUS | SWITCHOVER_EPOCH | SYNC_SCN            | REPLAYABLE_SCN      | READABLE_SCN        | RECOVERY_UNTIL_SCN  | LOG_MODE     | ARBITRATION_SERVICE_STATUS |
    +-----------+-------------+-------------+----------------------------+----------------------------+----------------------------------------+------------------------------------------------------------------+-------------------+--------------------+--------+---------------+--------+-------------+-------------------+------------------+---------------------+---------------------+---------------------+---------------------+--------------+----------------------------+
    |      1004 | mq_t1       | USER        | 2023-01-04 18:32:08.212745 | 2023-01-04 18:32:33.343667 | sa128_obv4_1;sa128_obv4_2,sa128_obv4_3 | FULL{1}@sa128_obv4_1, FULL{1}@sa128_obv4_2, FULL{1}@sa128_obv4_3 | NULL              | MYSQL              | NORMAL | NO            | NO     | PRIMARY     | NORMAL            |                0 | 1684396167132057328 | 1684396167132057328 | 1684396167051160964 | 4611686018427387903 | NOARCHIVELOG | DISABLED                   |
    +-----------+-------------+-------------+----------------------------+----------------------------+----------------------------------------+------------------------------------------------------------------+-------------------+--------------------+--------+---------------+--------+-------------+-------------------+------------------+---------------------+---------------------+---------------------+---------------------+--------------+----------------------------+
    1 row in set

   ```
 4. 查看租户 `mq_t1` 所拥有的 Unit。

   ```shell
    obclient> SELECT * FROM oceanbase.DBA_OB_UNITS WHERE TENANT_ID = 1004;
    +---------+-----------+--------+------------------+---------------+----------------------------+----------------------------+--------------+------------+----------+---------------------+-----------------------+----------------+----------------+---------+---------+-------------+---------------+----------+----------+-------------+
    | UNIT_ID | TENANT_ID | STATUS | RESOURCE_POOL_ID | UNIT_GROUP_ID | CREATE_TIME                | MODIFY_TIME                | ZONE         | SVR_IP     | SVR_PORT | MIGRATE_FROM_SVR_IP | MIGRATE_FROM_SVR_PORT | MANUAL_MIGRATE | UNIT_CONFIG_ID | MAX_CPU | MIN_CPU | MEMORY_SIZE | LOG_DISK_SIZE | MAX_IOPS | MIN_IOPS | IOPS_WEIGHT |
    +---------+-----------+--------+------------------+---------------+----------------------------+----------------------------+--------------+------------+----------+---------------------+-----------------------+----------------+----------------+---------+---------+-------------+---------------+----------+----------+-------------+
    |    1004 |      1004 | ACTIVE |             1005 |          1003 | 2023-01-04 11:48:36.582413 | 2023-01-04 18:32:08.215935 | sa128_obv4_1 | xx.xx.xx.47  |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1005 |      1004 | ACTIVE |             1005 |          1003 | 2023-01-04 11:48:36.591414 | 2023-01-04 18:32:08.215935 | sa128_obv4_2 | xx.xx.xx.81 |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1006 |      1004 | ACTIVE |             1005 |          1003 | 2023-01-04 14:13:36.980799 | 2023-01-04 18:32:08.217005 | sa128_obv4_3 | xx.xx.xx.19 |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    +---------+-----------+--------+------------------+---------------+----------------------------+----------------------------+--------------+------------+----------+---------------------+-----------------------+----------------+----------------+---------+---------+-------------+---------------+----------+----------+-------------+
    3 rows in set

   ```
 5. 查看租户 `mq_t1` 目前所拥有的日志流。

   ```shell
    obclient> SELECT * FROM oceanbase.CDB_OB_LS WHERE TENANT_ID = 1004;
    +-----------+-------+--------+----------------------------------------+---------------+-------------+---------------------+----------+---------------------+---------------------+
    | TENANT_ID | LS_ID | STATUS | PRIMARY_ZONE                           | UNIT_GROUP_ID | LS_GROUP_ID | CREATE_SCN          | DROP_SCN | SYNC_SCN            | READABLE_SCN        |
    +-----------+-------+--------+----------------------------------------+---------------+-------------+---------------------+----------+---------------------+---------------------+
    |      1004 |     1 | NORMAL | sa128_obv4_1;sa128_obv4_2,sa128_obv4_3 |             0 |           0 |                NULL |     NULL | 1672847276585423284 | 1672847276297748492 |
    |      1004 |  1001 | NORMAL | sa128_obv4_1;sa128_obv4_2,sa128_obv4_3 |          1003 |        1001 | 1672828353411747395 |     NULL | 1672847283647357012 | 1672847283446006907 |
    +-----------+-------+--------+----------------------------------------+---------------+-------------+---------------------+----------+---------------------+---------------------+
    2 rows in set

   ```
 6. 把租户 `mq_t1` 的 `UNIT_NUM` 修改为 2。

   ```shell
    obclient> ALTER RESOURCE TENANT mq_t1 UNIT_NUM = 2;

   ```
 7. 查看租户 `mq_t1` 修改后的 Unit。

   ```shell
    obclient> SELECT * FROM oceanbase.DBA_OB_UNITS WHERE TENANT_ID = 1004;
    +---------+-----------+--------+------------------+---------------+----------------------------+----------------------------+--------------+-------------+----------+---------------------+-----------------------+----------------+----------------+---------+---------+-------------+---------------+----------+----------+-------------+
    | UNIT_ID | TENANT_ID | STATUS | RESOURCE_POOL_ID | UNIT_GROUP_ID | CREATE_TIME                | MODIFY_TIME                | ZONE         | SVR_IP      | SVR_PORT | MIGRATE_FROM_SVR_IP | MIGRATE_FROM_SVR_PORT | MANUAL_MIGRATE | UNIT_CONFIG_ID | MAX_CPU | MIN_CPU | MEMORY_SIZE | LOG_DISK_SIZE | MAX_IOPS | MIN_IOPS | IOPS_WEIGHT |
    +---------+-----------+--------+------------------+---------------+----------------------------+----------------------------+--------------+-------------+----------+---------------------+-----------------------+----------------+----------------+---------+---------+-------------+---------------+----------+----------+-------------+
    |    1004 |      1004 | ACTIVE |             1005 |          1003 | 2023-01-04 11:48:36.582413 | 2023-01-04 18:32:08.215935 | sa128_obv4_1 | xx.xx.xx.47   |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1005 |      1004 | ACTIVE |             1005 |          1003 | 2023-01-04 11:48:36.591414 | 2023-01-04 18:32:08.215935 | sa128_obv4_2 | xx.xx.xx.81  |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1006 |      1004 | ACTIVE |             1005 |          1003 | 2023-01-04 14:13:36.980799 | 2023-01-04 18:32:08.217005 | sa128_obv4_3 | xx.xx.xx.19  |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1007 |      1004 | ACTIVE |             1005 |          1004 | 2023-01-04 23:50:57.989966 | 2023-01-04 23:50:57.989966 | sa128_obv4_1 | xx.xx.xx.43   |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1008 |      1004 | ACTIVE |             1005 |          1004 | 2023-01-04 23:50:57.995273 | 2023-01-04 23:50:57.995273 | sa128_obv4_2 | xx.xx.xx.106  |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    |    1009 |      1004 | ACTIVE |             1005 |          1004 | 2023-01-04 23:50:57.997360 | 2023-01-04 23:50:57.997360 | sa128_obv4_3 | xx.xx.xx.158 |     2882 | NULL                |                  NULL | NULL           |           1006 |       3 |       3 | 12884901888 |   38654705664 |    30000 |    30000 |           3 |
    +---------+-----------+--------+------------------+---------------+----------------------------+----------------------------+--------------+-------------+----------+---------------------+-----------------------+----------------+----------------+---------+---------+-------------+---------------+----------+----------+-------------+
    6 rows in set

   ```
 8. 查看租户 `mq_t1` 修改后的日志流。

   ```shell
    obclient> SELECT * FROM oceanbase.CDB_OB_LS WHERE TENANT_ID = 1004;
    +-----------+-------+--------+----------------------------------------+---------------+-------------+---------------------+----------+---------------------+---------------------+
    | TENANT_ID | LS_ID | STATUS | PRIMARY_ZONE                           | UNIT_GROUP_ID | LS_GROUP_ID | CREATE_SCN          | DROP_SCN | SYNC_SCN            | READABLE_SCN        |
    +-----------+-------+--------+----------------------------------------+---------------+-------------+---------------------+----------+---------------------+---------------------+
    |      1004 |     1 | NORMAL | sa128_obv4_1;sa128_obv4_2,sa128_obv4_3 |             0 |           0 |                NULL |     NULL | 1672847476919847432 | 1672847476694110593 |
    |      1004 |  1001 | NORMAL | sa128_obv4_1;sa128_obv4_2,sa128_obv4_3 |          1003 |        1001 | 1672828353411747395 |     NULL | 1672847481926946171 | 1672847481725653432 |
    |      1004 |  1002 | NORMAL | sa128_obv4_1;sa128_obv4_2,sa128_obv4_3 |          1004 |        1002 | 1672847466822734122 |     NULL | 1672847481906918109 | 1672847481705364375 |
    +-----------+-------+--------+----------------------------------------+---------------+-------------+---------------------+----------+---------------------+---------------------+
    3 rows in set

   ```

通过上述示例，将租户 `mq_t1` 的 Unit Number 从 1 变更为 2 。变更前租户在每个 Zone 的 Unit 个数为 1，对应的日志流个数为 1；变更后租户在每个 Zone 的 Unit 个数为 2，对应的日志流个数为 2，从而实现了租户扩容。

## 相关文档

- [租户扩缩容介绍](https://www.oceanbase.com/docs/common-oceanbase-database-cn-10000000001700598)。

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