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Author's profile photo Kathy Wang

Using a Backup ID Server for High Availability

Before we get into the backup ID Server, let’s review what an ID Server is, in case you’re new to SAP Replication Server or just need a refresh. When setting up a replication domain, the first SAP Replication Server you install is the ID Server. What does an ID Server do? Besides typical replication tasks, it also registers all SAP Replication Server instances and databases that reside within a replication domain for ID management. The ID Server must be running when you install new instances or databases to the domain.

A replication domain has only one active ID server, the primary ID server. You can set up a backup ID Server to ensure that some version of that server is always running, reducing potential downtime.

Why use a backup ID Server?

The backup ID Server reduces the risk of a single point of failure and improves overall availability. With the backup ID Server, you can:

  • Promote the backup ID Server to be the primary without interrupting daily work if the primary ID Server fails or becomes unavailable.
  • Switch the primary ID Server to a different SAP Replication Server. Prior to 15.7.1 SP300, after configuring the ID Server, it was difficult to reassign the job to another SAP Replication Server. Now, you can set any SAP Replication Server as the backup ID Server, and promote it to be the primary when necessary. For example, you may want to upgrade the machine that’s hosting the current primary ID Server, and need to take this machine offline. The backup ID Server can cover the downtime.

When you add or remove an SAP Replication Server or a database to or from the replication domain, the primary ID Server registers this new information, and then syncs up with the backup ID server. This sync up is done automatically by a Remote Procedure Call (RPC).

Use the sysadmin idserver command to configure the primary and backup ID Servers. You’ll need SAP Replication Server 15.7.1 SP300 or later for access to this command. Here, I’ll walk you through the typical workflow for adding a backup ID Server and promoting it to be the primary.

How do I add a backup ID Server?

Configure a backup ID Server on the primary ID Server (it won’t work anywhere else).

  1. On the primary ID Server – in this example, RS1 – run the following command to see the current ID Server settings:

    sysadmin idserver


    IDS             NAME        USER         STATUS

    ———-      ——–    ———–  ——–  

    primary         RS1         RS1_id_user  active

    backup          None        None         inactive

    We can see there’s no backup ID Server configured for the primary ID Server.

  2. On the SAP Replication Server that you want to configure as the backup ID Server (for example, RS2), create a user:

    create user RS2_id_user set <password>


    User ‘RS2_id_user’ is created.

    Grant sa to RS2_id_user


    Permission granted to user ‘RS2_id_user’.

  3. Back on the current primary ID Server, RS1, run the following command to configure RS2 as the backup ID Server:

    sysadmin idserver, config, backup, RS2, RS2_id_user, <password>


    Backup ID Server is configured.

    Then, view the current ID Server settings to verify your changes. Enter:

    sysadmin idserver


    IDS        NAME     USER          STATUS

    ——–   —–    ———–   ——-

    primary    RS1      RS1_id_user   active

    backup     RS2      RS2_id_user   active

How do I promote the backup ID Server to be the primary?

Let’s continue with the previous example:

  1. On the backup ID Server, RS2, run the following command:

    sysadmin idserver, config, ‘primary’, RS2, RS2_id_user, <password>


    This backup ID Server is promoted to primary ID Server.

    Then, to confirm your changes, enter:

    sysadmin idserver


    IDS         NAME      USER            STATUS

    ——–    ——    ————    ——–

    primary     RS2       RS2_id_user     active

    backup      NONE      NONE            inactive

    The previous primary ID Server, RS1, becomes a normal SAP Replication Server – it doesn’t become the backup. Since you’re left with only one ID server, you can add a new backup ID Server for the new primary ID Server, RS2.

  2. On the other SAP Replication Server instances in this domain, run the following command to change the primary ID Server to RS2 for each server.

    sysadmin idserver, config, ‘primary’, RS2, RS2_id_user, <password>


    Note: In a mixed-version system, for SAP Replication Server instances prior to 15.7.1 SP300, you need to manually update the configuration file and change the ID Server name to the new primary ID Server, then restart.

For more information about the backup ID Server, please refer to SAP Replication Server Reference Manual.

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      Author's profile photo Former Member
      Former Member

      Very good article! What REP Server version is required :15.7.1 SP300+ ?

      On my SP102, 'sysadmin idserver' does not exist:

      1> sysadmin idserver

      2> go

      Msg 16024, Level 12, State 0:

      Server 'CISTESTMU_PRS':

      SYSADMIN function 'idserver' is not valid.

      Author's profile photo Kathy Wang
      Kathy Wang
      Blog Post Author

      Hi Vincent,

      I'm glad you like the article. Yes, you'll need 15.7.1 SP300 or later to use the sysadmin idserver command. I also updated the article to include this information.



      Author's profile photo Kathy Wang
      Kathy Wang
      Blog Post Author

      Hi Mark,

      I like your blog about moving ID Server functionality to a new repserver. Thanks for sharing.