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The software stores all information for the CommCell in a SQL database and the Windows NT, Windows 2000, and Windows 2003 registries. It is critical to be able to retrieve this information in the case of a disaster or system failure. This metadata and Windows registry data are backed up during a Disaster Recovery Backup using two phases. This data can then be restored using the Commserver Recovery Tool.
Disaster Recovery backs up the following types of data:
| Metadata | Metadata includes the Microsoft SQL Server database that holds information about all CommCell database components (including clients and media configuration). |
| Windows registry | The Windows registry is a central resource from which the Windows operating system obtains many of the system’s operating parameters. |
| Firewall Configuration Files | The firewall configuration files (FwPeers.txt, FwHosts.txt and FwPorts.txt) are also included in the Disaster Recovery backup. If necessary, the entries associated with Clients/MediaAgents on the other side of the firewall from the CommServe can be restored in the event of a CommServe re-build. Note that a restore of the disaster recovery backup does not automatically restore the firewall files. To restore these files, manually select these files for restore from the Commserver Recovery Tool. See Restore a Disaster Recovery Backup for step-by-step instructions. |
The following types of Disaster Recovery Backups are supported:
| Full | Does a complete backup of CommServe database. |
| Differential | Backs up only that data in the CommServe database that has changed since the last full backup. |
Regardless of the backup type, the registry hive is always fully backed up.
Disaster Recovery Backups are done in two phases. The first phase backs up Disaster Recovery Backup data to a local or network path. If necessary, a network path pointing to the hot-site can be established. The second phase backs up data to media using a Disaster Recovery Backup storage policy.
Disaster Recovery Backup will check the CommServe database for any type of corruption. If database corruption is detected, all CommServe job activities are disabled. Contact your software provider for assistance with database corruption.
NOTE: By default, when a Disaster Recovery Backup detects database corruption, all CommServe job activities are disabled. To allow CommServe job activities to continue regardless of database corruption use the DisableActivityOnDbCorruption registry key.
This phase does a Disaster Recovery Backup to the destination File System directory chosen during the installation of the CommServe (a local drive on the CommServe or a network destination). This directory can be changed from the DR Backup dialog box in the Control Panel of the CommCell Console. If a network destination is chosen, then an appropriate user account must also be specified, as described in Designate the Disaster Recovery User Account.
SET_XXX directories are created under the specified destination. Each set holds information about the metadata and the registry. It contains the following files:
| File | Description |
| commserv_FULL.dmp | The database full backup file. |
| commserv_DIFF_xxx.dmp | The database differential backup file. |
| commserv_hive.reg | The CommServe registry full backup file. |
| commserv_hive_xxx.reg | The CommServe registry differential backup file. |
| some other registry files | Depends on the software module installed. |
Data is backed up from the SQL server and is written to the user-defined destination. If this phase is unable to get a response from the SQL server, the software will retry up to 10 times at 30 minute intervals. If the software can get the data but cannot write to the user defined destination, it will retry the creation the directory structure specified for the Disaster Recovery Backup destination. If it cannot then it will directly go to the second phase.
In Phase 2, a copy of the data backed up in Phase 1 and non-active log files is written to media using a Disaster Recovery Backup or standard storage policy.
Though it is recommended to use a Disaster Recovery Backup storage policy in your configuration, standard storage policies can be used as well. If you select a standard storage policy for your configuration, the media will contain a mix of Disaster Recovery Backup data as well as standard backup data. This is not a recommended configuration because the retention rules of the standard storage policy will apply to all the data written to the media for that storage policy regardless of data type, standard backup versus Disaster Recovery Backup data. If the storage policy's retention rules are met, the data will be aged; and if this occurs prior to running another Disaster Recovery Backup, the Disaster Recovery Backup data will be lost.
NOTE: If the software cannot write data to the media for any reason, it will retry up to ten times at 30 minute intervals. By default, Disaster Recovery Backup data written to media in Phase 2 is retained indefinitely, but can be changed from the DR Backup dialog box.
For more information on Disaster Recovery Backup storage policies, see Storage Policies.
Disaster Recovery Backup data can be restored at any production site or a hot-site any time using the Commserver Recovery Tool; however, the operation must be run on a CommServe machine that does not have any other platforms installed, e.g., MediaAgents, iDataAgents. Running the restore on a CommServe-only machine ensures that conflicts caused by mismatched product versions or dynamic-link library (DLL) files are avoided. The backup data can be restored from the Phase 1 Destination (Disaster Recovery Backups on disk) or the Phase 2 Destination (Disaster Recovery Backups on media).
Disaster Recovery Backups of data on or after the 5.9.0 release of the software can also be restored by using the Restore DR Data to Disk option. For more information, see Restore by Jobs.
Disaster Recovery backups are located on a disk drive (SET files), and can be restored using the Commserver Recovery Tool. If the destination of these Disaster Recovery Backups is on a network drive, the SET file must be copied to a local disk drive to the CommServe before using the Commserver Recovery Tool. See Commserver Recovery Tool for more information.
If Disaster Recovery backup data is located on media, you must first restore the data from media using Media Explorer. After Media Explorer restores the data to the local computer, you can use the Commserver Recovery Tool to restore the data. For information on the Media Explorer, see Media Explorer.
NOTE: Prior to restoring Disaster Recovery Backup data in a clustered environment, you must first stop all system Services using the Service Control Manager.
The status in which a Disaster Recovery Backup job can finish is explained in the following flowchart:
This section describes the following:
You can change either the Disaster Recovery Backup Phase 1 or Phase 2 destination.
The Disaster Recovery Backup Phase 1 destination can be changed from the Phase1 Destination pane of the DR Backup dialog box.
The Disaster Recovery Backup Phase 2 destination can be changed from the Phase2 Destination pane.
If backups are going to a remote location, after installing the CommServe software, you need to identify the Windows user account under which Disaster Recovery Backups are to be conducted. In order for Disaster Recovery Backups to work successfully on the network path, the specified Windows account must be a domain administrative account for the domain containing the Disaster Recovery backup destination directory.
You can designate the Disaster Recovery Backup user account from the Change User Account dialog box.
You can determine the number of Disaster Recovery backups to retain on disk and media.
When the metadata is backed up, it remains valid (available for restoration) for a period of time determined by the number of backup sets to retain. The retention rule is determined by the number of successful full backup cycles to be maintained.
The number of Disaster Recovery backup sets is preset to five full backups during installation. This can be changed from the DR Backup dialog box. This retention count refers to the number of backup sets created during Phase 1 of the Disaster Recovery Backup. Retention time for copies written to media drives during Phase 2 are determined by the characteristics of the Disaster Recovery Backup storage policy.
After each successful Disaster Recovery Backup, the system checks to see if the number of retained successful backup sets has exceeded the number of sets to retain. If expired data exists, it is automatically pruned. However, if the Disaster Recovery backup finished in Phase 2 with the status of Completed With One or More Errors, those backups sets that were not successfully copied to media will not be pruned from the disk.
NOTE: If a Disaster Recovery Backup job returns with a status of Completed With One or More Errors, the data or partial sets will be kept for 90 days and removed when the next Disaster Recovery Backup is run. The number of days partial Disaster Recovery Backup data will be retained before it is aged can be changed from the default of 90 days using the SetLifeSpanForFailedDR registry key.
A cycle begins with the successful completion of a full backup and includes all differential backups up to the next full backup. A cycle is not complete until the full backup that follows it has successfully completed. A cycle is considered successful only if the last differential backup of the set succeeds.
The final differential backup must be successful in order to restore the CommServe database to the point at which the cycle completed, regardless of whether any intermediate differential backups failed. It is the final differential backup that includes all changes to the data since the time of the initial, full backup. However, if the final differential is unsuccessful, the CommServe cannot be restored to the point in time at which the cycle completed; therefore, if the final differential is unsuccessful, that cycle is not counted towards the retention rule.
Disaster Recovery Backups are retained on media, depending on the retention rule of the Disaster Recovery Backup storage policy. After the retention rule of the storage policy has expired, the Disaster Recovery Backup data can be pruned using the data aging operation. See Data Aging for more information.
You can set the number of Disaster Recovery Backups to retain on media from the Number of full Metadata Backups to be retained field of the DR Backup dialog box.
This section describes how to run or schedule a Disaster Recovery Backup, view backup history, and the related reports. By default, a full Disaster Recovery Backup is run every day at 5:00pm.
Disaster Recovery Backups will run only when the SQL server is run as a system account (on a non-clustered computer). On a clustered computer, Disaster Recovery Backups will run only when the SQL server is run on a Windows account.
The number of times these full backups occur depend on the following:
You can run or schedule a Disaster Recovery Backup from the Disaster Recovery Backup Options dialog box. From this dialog box, you can select the type of backup operation, Full or Differential, as well as the option to Shrink the CommServe database before the DR backup, which will compress the database and database log file prior to the backup operation. This is useful if free space on the CommServe computer is an issue. If space is not an issue, it is not necessary to select this option.
The history of Disaster Recovery Backups allows you to view the status of an Disaster Recovery Backup job and the time the job started and ended. You can also view the media that job used and the events of the job.
See Admin Job History for more information on Disaster Recovery Backup job history.
You can click the Job Retry tab in the Disaster Recovery Backup Options dialog box to access the Job Retries and Job Running Time options, when you perform a Disaster Recovery Backup operation.
You can also specify the maximum number of allowed restart attempts and the interval between restart attempts for all Disaster Recovery Backup jobs. For procedures, see Specify Job Restartability for the CommCell.
For more information on these subjects, see Job Restart and Job Running Time.
See Commserver Recovery Tool for more information on Commserver Recovery Tool.