# Preparing to create an RDS for Db2 replica
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Before creating an RDS for Db2 replica, you must complete the following tasks for successful replication. These tasks help prevent common issues and ensure optimal performance.

## Task 1: Enable automatic backups
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Before a DB instance can serve as a source DB instance, you must enable automatic backups on the source DB instance. This is a prerequisite for all replica creation operations. To learn how to perform this procedure, see [Enabling automated backups](USER_WorkingWithAutomatedBackups.Enabling.md).

For information about backups specific to Db2 replicas, see [Working with RDS for Db2 replica backups](db2-read-replicas.backups.md).

## Task 2: Plan compute and storage resources
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Ensure that the source DB instance and its replicas are sized properly, in terms of compute and storage, to suit their operational load. If a replica reaches compute, network, or storage resource capacity, the replica stops receiving or applying changes from its source. For information about monitoring replica performance and resource utilization, see [Monitoring read replication](USER_ReadRepl.Monitoring.md). 

RDS for Db2 doesn't intervene to mitigate high replica lag between a source DB instance and its replicas. If you experience high replica lag, see [Monitoring Db2 replication lag](db2-troubleshooting-replicas.md#db2-troubleshooting-replicas-lag) for troubleshooting guidance. 

You can modify the storage and CPU resources of a replica independently from its source and other replicas. For more information, see [Modifying an Amazon RDS DB instance](Overview.DBInstance.Modifying.md).

## Task 3: Prepare databases
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Before creating a replica, confirm that your databases are ready based on the following points:
+ The DB instance contains all databases that you want present on the DB instance. After replica creation, you can't create, drop, or native restore a database on the DB instance. Any calls to the [rdsadmin.create\$1database](db2-sp-managing-databases.md#db2-sp-create-database), [rdsadmin.drop\$1database](db2-sp-managing-databases.md#db2-sp-drop-database), or [rdsadmin.restore\$1database](db2-sp-managing-databases.md#db2-sp-restore-database) stored procedures fail.
+ All databases on the DB instance are in an active state. If any database is in an inactive state, replica creation will fail. For information about activating databases, see [Stored procedures for databases for RDS for Db2](db2-sp-managing-databases.md).

## Next steps
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After completing all the preparation tasks, you are ready to create a Db2 replica.
+ To create a read-only replica, see [Creating a read replica](USER_ReadRepl.Create.md).
+ To create a standby replica, see [Creating a standby Db2 replica](db2-read-replicas.creating-in-standby-mode.md).