# Setting the Redundancy Level

To use [availability groups](https://docs.singlestore.com/db/v9.1/introduction/distributed-architecture/high-availability.md) in a cluster, you need to set the [redundancy level,](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/high-availability-and-disaster-recovery/managing-high-availability.md) which specifies the maximum number (1 or 2) of availability groups.

## Setting the Engine Variable

Use the `SET GLOBAL` command to change `redundancy_level` engine variable on the master aggregator at run time:

```sql
SET @@GLOBAL.redundancy_level = {1 | 2};

```

You can inspect the current value with the `SELECT GLOBAL` command:

```sql
SELECT @@GLOBAL.redundancy_level;

```

## Adding and Removing Leaves

Use [ADD LEAF](https://docs.singlestore.com/db/v9.1/reference/sql-reference/cluster-management-commands/add-leaf.md) and [REMOVE LEAF](https://docs.singlestore.com/db/v9.1/reference/sql-reference/cluster-management-commands/remove-leaf.md) to add leaves to, and remove leaves from, a SingleStore cluster.

## Adding and Removing Child Aggregators

Use [ADD AGGREGATOR](https://docs.singlestore.com/db/v9.1/reference/sql-reference/cluster-management-commands/add-aggregator.md) and [REMOVE AGGREGATOR](https://docs.singlestore.com/db/v9.1/reference/sql-reference/cluster-management-commands/remove-aggregator.md) to add and remove child aggregators from a SingleStore cluster.

> **📝 Note**: These commands must be run against the Master Aggregator.

***

Modified at: March 13, 2026

Source: [/db/v9.1/user-and-cluster-administration/maintain-your-cluster/administering-a-cluster/setting-the-redundancy-level/](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/maintain-your-cluster/administering-a-cluster/setting-the-redundancy-level/)

(An index of the documentation is available at /llms.txt)