Disaster Recovery - SQL Server iDataAgent

Table of Contents

Planning for a Disaster Recovery

Rebuilding the Operating System

Rebuilding the SQL Server Instance

Rebuilding the Master Database (Quick Rebuild)

Rebuilding Each SQL Server Instance (When Quick Rebuild Does Not work)

Restoring the SQL Server Instance

Planning for a Disaster Recovery

Before you begin a disaster recovery, make sure to plan for disaster recovery as follows:

Building a Standby Server for Disaster Recovery

You can build a standby server for quick recovery and ensure that the standby database is always kept in a near ready state. If you plan to adopt this method follow the steps described in Replication Using Warm Database Restore.

Managing Backups

As a best practice, it is recommended that you group databases into multiple subclients as follows:

• Add larger databases into separate subclients.
• Add small databases together into one or more subclients. This is important for the following reasons:
  • During Disaster recovery, when you have to quickly rebuild the entire instance, you can concurrently restore all the subclients together.
  • During Backup failures, the backup will restart from the beginning of the database instead of from the beginning of the entire instance. Similarly, this will ensure that large database backups are not affected by restarts from a smaller database.
• Once the subclients are created,  schedule frequent backups for dynamic data and regular backup schedules for static data in the SQL Server.

Rebuilding the Operating System

In the case of disaster recovery, where a full system restore is required, you must first rebuild the system to exactly the state as it existed before the problem. Use the following steps to rebuild the operating system:

1. Rebuild the hardware if needed.
2. Install the same version of the Windows operating system with the same patches that were previously installed.
3. Configure the client with the same networking parameters and passwords that were previously set.
4. Edit the host file of the client to include the CommServe name.
5. Install the Windows File System iDataAgent on the client.

   In a clustered environment, you must reinstall to the same virtual node as was being used previously.

6. Perform a full system restore of the Windows File System iDataAgent.

After you rebuild the operating system, if the SQL Server instance starts, use the steps in Restore the SQL Server Instance to restore the data.

Rebuilding the SQL Server Instance

After rebuilding the operating system, if the SQL Server Instance does not start, you need to rebuild the instance and then restore it to the current state. You can rebuild the instance by rebuilding the master database or by reinstalling each instance.

Rebuilding the Master Database (Quick Rebuild)

The master database can be rebuild using SQL Server or SQL Server Express.

If the Master Database Exist

1. Insert the SQL Server installation media into the disc drive. If you are using SQL Server Express, download the Express kit and extract the contents to a local directory.
2. From the command prompt, navigate to the disc drive or the extracted directory and run the command for rebuilding the master database.

   For SQL 2005:

   start /wait setup.exe /qn INSTANCENAME=<InstanceName> REINSTALL=SQL_Engine REBUILDDATABASE=1 SAPWD=<NewStrongPassword>  REINSTALLMODE=vomus

   where:

   /qn = suppresses all setup dialog boxes and error messages.

   /qb = allows display of basic setup dialog boxes and error messages.

   For SQL 2008:

   Setup /QUIET /ACTION=REBUILDDATABASE /INSTANCENAME=InstanceName /SQLSYSADMINACCOUNTS=accounts [ /SAPWD=StrongPassword ] [ /SQLCOLLATION=CollationName ]

   where:

   /QUIET or /Q = setup runs without any user interface.

3. From the command prompt, run Services.msc
4. Right-click the SQL Server instance and select Start.
5. Restore the SQL Server Instance

IF the Master Database Does Not Exist

In case when the master database is not available, use the following steps to rebuild the master database:

1. Navigate to the directory where the SQL Server is installed, usually C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL.
2. Open the Template Data folder and verify that there is a copy of the system databases created automatically during the original install.
3. Copy the missing files and paste them into the Data directory (C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data).
4. From the command prompt, run Services.msc
5. In the Services window, right-click the SQL Server instance and select Start.l

Rebuilding Each SQL Server Instance (When Quick Rebuild Does Not work)

If the quick rebuild method does not work, you can rebuild the SQL Server by reinstalling each SQL Server instance.

1. Uninstall the existing SQL Server instances.
2. Install the SQL Server instances using the same installation paths and configuration settings as the previous installation.

   Paths and instance name information of the original installation can be viewed by browsing the backup data from the CommCell Browser.

3. From the command prompt, run Services.msc
4. In the Services window, right-click each SQL Server instance and select Start.

Restoring the SQL Server Instance

Once you have rebuild the SQL Server instance, you can restore the instance using the following steps:

1. Stop any application or services that are accessing the SQL databases.
2. Restore the system databases.
3. Restore the user databases to a consistent point in time in the order that you require.

   When restoring non-system databases, each database being restored runs as a separate job and a separate SQL process. Therefore, avoid starting more restores (jobs) than your SQL server and available memory can handle.