Replication Using Warm Database Restore

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Replication Using Warm Database Restore

This type of restore is also called Hot Server Restore. You can keep up-to-date copies of the production databases on alternate servers, thus minimizing down time in cases where the production database server has failed.

The advantages of Warm Database Restore over a traditional restore scenario is that the database is always kept in a near ready state. In the case of disaster, users do not need to wait for the time it would take to restore the database in its entirety. Only the latest backup may need to be applied to the target database before turning the application over to use it.

Prerequisites

Review the following requirements before performing a Warm Database Restore:

  • The primary SQL server and hot standby server must be clients of the same CommServe and have the SQL Server iDataAgent installed on each computer.
  • The primary SQL server must be able to communicate with the hot standby server with one of the following network configurations:
    • Local Area Network (LAN) in the same domain
    • Local Area Network (LAN) in a different domain
    • Wide Area Network (WAN)
  • Two licenses for SQL Server iDataAgent is required.

Setting Up the Standby Server

Use the following steps to setup the standby server:

  1. Install the Microsoft SQL Server iDataAgent on the hot standby server computer.
  2. Perform a full backup of the SQL Server databases on the primary server.
  3. Perform a restore of the last full backup of the primary database, as well as any differential or transaction log backups completed since the database’s last full backup.
  4. Schedule routine differential or transaction log backups of the SQL Server databases on the primary server.
  5. Schedule routine restore operations of the Latest Backup Data in the Standby Server.
    • Matching the restore schedule with a backup schedule on the source database automatically keeps the restored databases in the Standby Server up-to-date.
    • If you wish to include only the transaction log backups completed since the last restore operation, you must select the Apply Log Backups Only option after selecting Latest Backup Data in the SQL Restore Options dialog box. The restore operation will then skip any full backup jobs completed since the last restore operation.

      If you do not select the Apply Log Backups Only option and the database already exists, all backup jobs completed since the last restore operation will automatically be restored.

      If you do not select the Apply Log Backups Only option and the database does not already exist, the software will automatically perform a full restore of the database.

Using the SQL Server Database(s) on the Hot Standby Server

In the event of a failure in the primary server you can use the hot standby server by bringing the databases online. Use the following steps to bring the database online.
  1. From the CommCell Browser, navigate to Client Computers | <Client> | SQL Server.
  2. Right-click the instance and then click All Tasks | Browse Backup Data.
  3. Click OK.
  4. In the Browse window, select the databases that you want to recover in the right pane and click Recover All Selected.
  5. Click Recover Only.
  6. Click OK.

You can also bring the databases online by recovering the database from the SQL Server Enterprise Manager.

No further restore operations may be performed to the hot standby server’s databases once the databases have been recovered.

If you wish to perform more restore operations to the hot standby server after recovering the databases, you must setup the hot standby server once again.

Performing Disaster Recovery Operations for the Primary SQL Server Database(s)

If the primary server's databases is lost, you can restore the databases from the hot standby server's databases by performing the appropriate in-place restore operation.

If the entire primary server is lost, you must perform a full system restore.

Once the full system restore has completed, you will need to set up the hot standby server again by repeating the steps outlined in this procedure.