Cloning with Instance Data Replication

  • Release version: Yokohama
  • Updated January 30, 2025
  • 4 minutes to read
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    Summary of Cloning with Instance Data Replication

    Instance Data Replication (IDR) enables ServiceNow customers to clone their databases between instances while managing the replication configuration effectively. Cloning with IDR requires careful handling of certain tables to preserve or exclude data and configurations. There are multiple methods to transfer IDR configurations, including capturing them in update sets or cloning the entire instance with selective inclusion or exclusion of IDR data.

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    Key Methods for Copying IDR Configurations

    • Update Sets: Capture IDR replication configurations such as fields, filters, and data transformations using the Track in Update Set option. This method moves configuration changes without transferring replicated data.
    • Clone Profiles: Clone the entire database from one instance to another, including data and IDR configurations, with options to preserve or exclude IDR tables based on the cloning use case.

    IDR Cloning Use Cases

    Different cloning scenarios require specific handling of IDR tables and configurations:

    • Recurring Clone: Used for regular cloning where the target instance’s existing IDR configuration should remain unchanged. Update the cloning profile to exclude IDR replication configuration to avoid conflicts. Post-clone, you can copy IDR configurations via update sets if needed.
    • True Clone: Copies the entire IDR replication configuration from the source to the target instance, effectively inheriting all settings. After cloning, resubscribe consumer instances to the new producer to ensure proper data replication.
    • Migration Clone: Combines a true clone with preservation of the target instance’s existing replication configuration. This involves capturing current replication sets on the target via update sets before cloning, then importing and re-creating replication sets post-clone to maintain both source and target configurations.

    Practical Guidelines

    • Before cloning, verify successful IDR configuration and replication on involved instances.
    • Modify preserve and exclude lists in the clone profile based on the use case to control which IDR tables are cloned.
    • After true or migration clones, re-create or resubscribe replication sets on the target instance to maintain replication integrity.

    Value for ServiceNow Customers

    By following these cloning strategies, customers can confidently manage their instance data replication during database cloning activities, ensuring data consistency and replication continuity across environments. This is essential when provisioning new environments, migrating configurations, or performing regular cloning without disrupting ongoing replication processes.

    Ensure that certain tables are preserved or excluded to clone your database from one instance to another successfully with Instance Data Replication (IDR).

    There are multiple methods for copying an IDR configuration from one instance to another.

    Capture the configuration in an update set

    An update set captures a group of configuration changes that you can move from one instance to another but doesn’t include data that a producer replicates to a consumer. You can capture a snapshot of an IDR replication configuration, including selected fields, filters, or data transformations using the Track in Update Set option, and then copy it to another instance using an update set. See Deploying a replication configuration from one instance to another in Instance Data Replication.

    Copy the configuration using a clone profile
    Cloning your instance copies everything in the database from one instance to another, including the data and the IDR replication configuration.

    Before you clone your instance, you must determine whether to exclude or include your IDR replication configuration.

    For details on cloning, see .

    IDR cloning use cases

    You must preserve and exclude different sets of IDR tables in your cloning profile depending on your cloning use case.

    Recurring clone
    In this use case, you clone your source instance regularly without affecting the existing IDR configuration on the target instance.

    For example, you configure IDR to replicate data from instance A to instance B. You determine that you must clone the database from instance A to another instance called instance C. Instance A and instance C both have IDR configured with different replication configurations. When you clone the database from instance A to instance C, you don’t want to clone any of the IDR replication configuration from A to C.

    Note:
    If you regularly clone data from your source instance to your target instance, and find that you need to copy the IDR replication configuration from the source instance to the target instance, use the Track in update set feature to copy the IDR to the target instance.

    To clone your database from one instance to another without affecting the IDR configuration on the target instance, you must update the preserve and exclude lists in your cloning profile according to the Recurring Clone use case described in KB0965218.

    True clone
    In this use case, you clone your source instance to your target instance and include the complete IDR replication configuration. The target instance inherits everything from the source. After the clone is finished, you must resubscribe all consumer instances to the target instance.

    For example, you decide to provision a new production instance from a non-production instance that already has IDR configured. When you clone the non-production instance, the new production instance inherits everything from the non-production instance. To ensure that data replicates from the production instance and not the non-production instance, you resubscribe all consumer instances to the new production instance.

    To clone your database and copy the current IDR configuration to the target instance, you must update the preserve and exclude lists in your cloning profile according to the True Clone use case described in KB0965218.

    Migration clone
    In this use case, you clone your source instance to the target instance, including the complete IDR replication configuration from the source instance, while preserving the target instance’s replication configuration.

    The migration clone involves performing a true clone, but with additional steps.

    1. On the target instance, you create an update set and use the Track in update set feature to upload the existing replication sets on the target instance into the update set.
    2. Perform a true clone.
    3. After performing the true clone, you import the update set to the target instances, and you set up replication sets using entry sets to preserve the configuration.
    Table 1. Comparing IDR cloning use cases
    Use case Description Prerequisites Post requisites
    Recurring clone Clone your source instance to your target instance regularly but exclude your IDR replication configuration.

    When complete,replication sets on the target instance should not be changed.

    		 Verify that IDR is configured correctly, and that replication is successful on both the source and target instances. After performing a recurring clone, you can copy the IDR replication configuration from the source instance to the target instance using the Track in update set feature.
    True clone Clone your source instance to your target instance and copy your IDR configuration to the target instance.

    When complete, entry sets from the source instance should be cloned to the target instance.

    		 Verify that IDR is configured correctly, and that replication is successful on the source instance. After performing a true clone, you must perform the following actions on the target instance:
    1. Re-create the replication sets using the cloned entry sets from the source instance.
    2. Resubscribe each consumer to the newly-provisioned producer.
    Migration clone Clone your source instance to your target instance and copy your IDR configuration to the target instance, while preserving the target instance’s replication configuration.

    When complete, entry sets from the source instance should be cloned to the target instance.
    1. Capture the existing replication sets on the target instance in an update set using the Track in update set feature.
    2. Perform a true clone.
    		 After performing the true clone, you must perform the following actions on the target instance:
    1. Import the update set.
    2. Re-create the target replication sets using the entry sets captured in the update set.
    3. Re-create the source replication sets using the cloned entry sets from the source instance.