2 Migrating from Legato to Oracle Secure Backup

Legato and Oracle Secure Backup

In previous database releases, Legato Storage Manager and Legato Single Server Version were bundled with Oracle Database. Legato Single Server Version included a single-server version of the EMC Legato NetWorker and the NetWorker Module for Oracle that together enabled administrators to back up Oracle databases to tape.

Oracle now provides Oracle Secure Backup and Oracle Secure Backup Express as its media management solution. Oracle Secure Backup Express is recommended as the best replacement for previously bundled versions of Legato. The instructions in this chapter refer to Oracle Secure Backup, but apply equally to either Oracle Secure Backup or Oracle Secure Backup Express.

The Oracle Secure Backup media management software enables you to back up files on your file system to tape and is also fully integrated with RMAN to provide data protection services for one or more Oracle databases in a networked environment.

This chapter describes best practices for migrating from a Legato environment to an Oracle Secure Backup environment. This chapter does not explain how to install or configure Oracle Secure Backup. These tasks are explained in Oracle Secure Backup Installation Guide and Oracle Secure Backup Administrator's Guide.

Although the focus of this chapter is on migrating from Legato to Oracle Secure Backup, many of the practices and recommendations described in this chapter are applicable to migration from other media management products.

Overview of the Migration Procedure

The basic stages of the migration from Legato to Oracle Secure Backup are as follows:

1. Verify that the components of your Legato infrastructure work with Oracle Secure Backup.

   "Checking Compatibility" explains this stage.

2. Plan the Oracle Secure Backup administrative domain. In this stage, you must consider the environment where Legato is currently used and how you will deploy Oracle Secure Backup there.

   "Planning the Oracle Secure Backup Domain" explains this stage.

3. Install Oracle Secure Backup and either discard, maintain, or copy your legacy Legato backups.

   "Managing Legato Backups When Migrating to Oracle Secure Backup" explains this stage.

Media Management Architecture

Typically, Legato environments include a small to medium number of hosts, each of which backs up data to a small number of locally attached tape devices. You can use the same model with Oracle Secure Backup and configure each host to use locally attached devices. Alternatively, you can consolidate your backup environment so that backups are sent to centralized media servers within a single administrative domain. This section describes both approaches.

Multiple-Domain Architecture

A multiple-domain architecture most closely corresponds to your existing Legato architecture. In this architecture, you install Oracle Secure Backup on every host on which you previously installed Legato and leave the tape devices as they are. Each host functions as administrative server, media server, and client.

Figure 2-1 illustrates a sample network of three hosts, each of which runs Legato in conjunction with an Oracle database and has a locally attached tape device. During migration, you install Oracle Secure Backup on each host and assign it the roles of client, media server, and administrative server.

Figure 2-1 Multiple-Domain Architecture

Description of "Figure 2-1 Multiple-Domain Architecture"

To implement this architecture, follow these instructions:

1. Install Oracle Secure Backup on every Oracle database host.

2. Assign each host the role of administrative server, media server, and client.

   Make sure to answer yes when prompted to configure your Oracle homes to use the Oracle Secure Backup SBT interface for database backups.

3. Configure the tape devices attached to each host.

See Also:

Oracle Secure Backup Installation Guide to learn how to install and configure Oracle Secure Backup

Single-Domain Architecture

This architecture offers the benefits of centralized media and backup catalog management. Figure 2-2 illustrates the same Legato network depicted in Figure 2-1. During migration, you install Oracle Secure Backup on each of the three hosts and assign it the role of client. The tape devices are centralized on a fourth host, which is the media server. A fifth host is a dedicated administrative server, which manages the administrative domain.

Figure 2-2 Single-Domain Architecture

Description of "Figure 2-2 Single-Domain Architecture"

To implement this architecture, follow these instructions:

1. Identify the host that will be the administrative server and install Oracle Secure Backup on this host.

   You can configure a new host to assume this role, as shown in Figure 2-2, or use an existing host. If you use an existing host, and if one of the hosts contains a centralized RMAN recovery catalog, then this host is a good candidate for the administrative server

2. Identify the hosts that will manage the tape devices and install Oracle Secure Backup on these hosts. Assign these hosts the role of media server.

3. Configure the tape devices attached to the media servers.

4. Install Oracle Secure Backup on the database hosts and assign them the client role.

   Make sure to answer yes when prompted to configure your Oracle homes to use the Oracle Secure Backup SBT interface for database backups.

See Also:

Oracle Secure Backup Installation Guide to learn how to install and configure Oracle Secure Backup

Backup Procedures and Scripts

Oracle Secure Backup supports both file system and database backups. Depending on how you implement your Oracle Secure Backup environment, you may need to modify your backup procedures and scripts.

Discarding Legato Backups

In this option, you uninstall Legato from a database host, install Oracle Secure Backup, and reuse or discard the old Legato tapes. This option requires no overhead and is suitable for databases that meet either of the following criteria:

• Databases with no historical retention requirements

• Databases whose primary backups are located on disk rather than on tape

Only discard your legacy tape backups if you are able to take a new full backup immediately after installing Oracle Secure Backup.

To migrate to Oracle Secure Backup and discard legacy tape backups:

1. Identify the databases to be backed up to the Oracle Secure Backup SBT interface.

2. Perform a consistent shutdown of the databases identified in the previous step.

   Note that you do not have to shut down the databases if your configuration meets both of the following criteria:

   • You are backing up to disk as well as to tape.

   • You have sufficient backups on disk to recover if a failure occurs during the migration.

   If your configuration does not meet the preceding criteria, then you risk losing data if a failure occurs before you make a new backup with Oracle Secure Backup.If you cannot shut down the database during the Oracle Secure Backup migration, and if you have no disk backups, then make a temporary disk backup. This backup protects you from failures during the migration. You can discard the temporary backup after making a backup with Oracle Secure Backup.

3. For each database, run the RMAN command DELETE BACKUP DEVICE TYPE sbt to remove its Legato backups.

4. Uninstall Legato from all hosts where it is no longer needed.

5. Install and configure Oracle Secure Backup on each host in your administrative domain according to the architecture that you chose in "Media Management Architecture".

   Oracle Secure Backup Installation Guide explains how to install and configure Oracle Secure Backup.

6. Modify your RMAN scripts to work with Oracle Secure Backup.

   As explained in "Database Backups", you may need to change the PARMS settings used by RMAN when backing up through the Legato interface. Oracle Database Backup and Recovery Advanced User's Guide to learn how to configure RMAN for use with a media manager.

7. Back up each database to tape.

   If you are not using disk backups, then back up the databases to tape before opening the database. If you use disk backups, then these backups protect you from failure until your scheduled backup time. Oracle Secure Backup Administrator's Guide explains how to back up a database with Oracle Secure Backup.

8. Verify that the new Oracle Secure Backup backups can be restored by using the RMAN RESTORE VALIDATE command.

9. Open the databases and make them available to users.

Retaining Legato Backups

In this option, you maintain dual Legato and Oracle Secure Backup installations on a host for as long as you need to restore backups from Legato. You must maintain the legacy Legato tapes along with the Oracle Secure Backup tapes.

This option may be suitable for databases that meet any of the following criteria:

• Databases with long retention requirements

• Databases where it is not desirable or feasible to copy older backups into Oracle Secure Backup

• Databases that cannot be shut down or left unprotected during migration

To migrate to Oracle Secure Backup and retain legacy backups in Legato:

1. Identify the databases to be backed up to the Oracle Secure Backup SBT interface.

2. Install and configure Oracle Secure Backup on each host in your administrative domain according to the architecture that you chose in "Media Management Architecture".

   Oracle Secure Backup Installation Guide explains how to install Oracle Secure Backup.

   Note:

   Because this strategy requires that Legato and Oracle Secure Backup co-exist for some time, consider how to allocate tape resources. Legato and Oracle Secure Backup cannot share tape resources.

3. Modify your RMAN scripts to work with Oracle Secure Backup.

   As explained in "Database Backups", you may need to change the PARMS settings used by RMAN when backing up through the Legato interface. See Oracle Secure Backup Administrator's Guide to learn how to configure RMAN for use with Oracle Secure Backup.

4. Create RMAN scripts to restore backups from Legato.

   There will a period of time during which you may need to restore backups from either Legato or Oracle Secure Backup. During this time, you need RMAN scripts to restore from Legato. These scripts should use manually allocated channels that specify the Legato shared library.

   Optionally, you can write restore scripts that reference both Legato and Oracle Secure Backup shared libraries, thereby enabling RMAN to restore backups from either Legato or Oracle Secure Backup. Example 2-1 shows a sample script of this type. When you run this script, RMAN automatically uses the correct channel to restore the required backups.

   Example 2-1 Specifying Legato and Oracle Secure Backup Libraries

   RUN
   {
     ALLOCATE CHANNEL c1 TYPE sbt
       PARMS 'SBT_LIBRARY=oracle_secure_backup_library';
     ALLOCATE CHANNEL c2 TYPE sbt
       PARMS 'SBT_LIBRARY=legato_library';
     RESTORE DATABASE;
     RECOVER DATABASE;
   }
   
   

5. Verify that you can back up files in the new Oracle Secure Backup environment.

   A small backup of the control file, a few datafiles, and a few archived redo logs is sufficient to test that you can back up.

6. Verify that you can restore files from both Legato and Oracle Secure Backup by using the RMAN RESTORE VALIDATE command.

7. When your Legato backups are no longer needed, perform the following tasks:

   • Uninstall Legato.

   • Discard the special restore scripts that you created to restore from Legato.

   • Reuse the Legato tape resources.