By deploying IBM Tivoli Storage Manager (TSM) backup and restore software, and using the Disaster Recovery Manager
(DRM) module, IT departments hope to ensure the ability to restore data in the event a disaster causes the loss of the primary copy of the data. Data backup is probably the most essential form of data protection and is the cornerstone of most disaster recovery (DR) plans. For companies that still resist the need to plan for disaster recovery, backups represent their minimum protection.
However, because of the very basic nature of backups, many IT professionals often don't give their backup infrastructure the attention it needs. Depending on the industry, IT professionals often consider their CRM or ERP server, or their email or financial application, the most critical system to recover in the event of a disaster. In most cases, however, the backup server should be the most critical. You can rebuild any system, but if backups were your only means of data protection, the backup server must be up first.
When disaster strikes, a number of IT elements we normally rely on for daily operations may be gone. You cannot simply hit the restore key following a disaster because you first have to "restore the restore key." Let's take a look at the often ignored TSM Disaster Recovery Manager module, which was designed to automate the recovery of Tivoli Storage Manager.
What is TSM Disaster Recovery Manager?
At a high level, the Disaster Recovery Manager allows a TSM administrator to manage the offsite media, the TSM database backups sent offsite and generate a recovery plan file to literally help automate the recovery of the Tivoli Storage Manager server.
Recovery plan file
The recovery plan file (not to be confused with the IT department's disaster recovery plan) is generated daily and is essentially a series of scripts and commands that replay all steps necessary to reconfigure your Tivoli Storage Manager server environment. This file contains all the information required to rebuild the TSM server and allows you to include as much customized information as you see fit for your environment.
Following a disaster, the recovery plan file can be broken down into user-readable components for specific instructions, such as the contact information about your offsite tape storage provider (vault service) as well as automated scripts or "macros" to configure tape devices, restore the TSM database (or catalog) and rebuild storage pools from offsite tape volumes.
In addition to including scripts and commands to recreate the Tivoli Storage Manager environment and whatever customized information was included manually, the recovery plan file contains vital information such as:
- Volume number of the Tivoli Storage Manager database backup tape(s) required to restore the database
- Licensing information
- List of all the offsite tapes needed to restore the storage pools and all its data
- Device configuration information (tape drives, library, etc.)
- Size of the preformatted disk space needed to restore the database
- A list of the volumes that are assumed to be destroyed (anything that was onsite when the file was generated)
- TSM server options files (configuration file)
A diligent Tivoli Storage Manager administrator should include enough customized detail, in addition to the default information generated by DRM, so that IT will be able to find everything needed to recover the TSM environment. A copy of this file must be sent offsite every time it is generated. If the copy is sent to your email, be sure the email server is not next to the TSM server.
The "Prepare" command and Disaster Recovery Manager
The "Prepare" command is the Tivoli Storage Manager Disaster Recovery Manager command that generates the recovery plan file described above. This command must be issued daily to generate an updated recovery plan file reflecting the daily changes to the environment. The timing of this command is also very important since it will generate a file that must contain the most recent information about the TSM server. This means it must be issued after the offsite bound tape volumes have been ejected from the library to be sent offsite, and after a TSM database backup was generated and ejected from the library to also be sent offsite. Each file has a unique identifier based on a timestamp.
The "Move DRMedia" command
The "Move DRMedia" command is used to manage offsite bound media and change its status within the TSM environment. A copy of storage pool volume that is in the library and is accessible is known as being in the "mountable" state. The other statuses include:
- Not mountable: The volume has been ejected from the library and ready to be sent offsite.
- Courier: The volume is in transit to the vault.
- Vault: The volume in stored in the vault.
- Vault retrieve: All data on the volume has been expired and it can be recalled for reuse.
- Courier retrieve: The volume is in transit back onsite.
- Onsite retrieve: The volume has arrived onsite.
These states help keep track of the various states the tape media is in. The status of volumes is changed via a command or a scripted command as the software is not actually aware of the media being in transit. The process may seem convoluted, but for large data centers that handle hundreds of tapes per day, it is easy to get tapes mixed up and lose track of where they are or should be going. The "query drmedia" command is used to track the state of offsite tape volumes.
There are multiple aspects of the Tivoli Storage Manager Disaster Recovery Manager that can be customized and automated to make offsite media management a lot easier. This short article only introduces the basic concept of the module, but more information on TSM best practices can be found in the Deployment Guide Series: IBM Tivoli Storage Manager V5.5.
Pierre Dorion is the data center practice director and a senior consultant with Long View Systems Inc. in Phoenix, Ariz., specializing in the areas of business continuity and DR planning services and corporate data protection.
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