Managing Backing Up and Restoring (Analysis Services)
Backing up lets administrators save a particular state of a Microsoft SQL Server Analysis Services database and its objects. Restoring lets administrators restore an Analysis Services database to a previous state. The reasons for doing backups include data recovery and preparation for audits. If you do not already have a backup plan and your data is valuable, you should design and implement plan as soon as possible. For a full backup that includes source data, you have to back up the database which contains detail data. In general, Analysis Services backups contain metadata and a subset of source data and/or aggregations, not the complete underlying detail data. However, if all objects are MOLAP, the backup contains metadata and source data.
One clear benefit of automating backup is that the data snapshot will always be as up-to-date as the automated frequency of backup specifies. Automated schedulers ensure that backups are not forgotten. Restoring a database can also be automated, and can be a good way to replicate data, but be sure to back up the encryption key file on the instance you replicate to. The synchronization feature is dedicated to replication of Analysis Services databases, but only for the data that is out of date. All of the features mentioned here can be implemented through the user interface, by way of XML/A commands or programmatically run through AMO. For more information about backup strategies, see Backup Strategies with SQL Server 2005 Analysis Services.
In SQL Server Analysis Services, administrators can back up an Analysis Services database to a single operating system file, regardless of size of the database. If the Analysis Services database contains remote partitions, the remote partitions can also be backed up. When you back up a database with remote partitions, all the remote partitions on each remote server are backed up to a single file on each of those remote servers respectively. Therefore, if you want to create those remote backups off their respective host computers, you will have to manually copy those files to the designated storage areas.
Backing up an Analysis Services database produces a backup file whose contents vary depending upon the storage mode used by the database objects. This difference in backup content results from the fact that each storage mode actually stores a different set of information within an Analysis Services database. For example, hybrid OLAP (HOLAP) partitions and dimensions store aggregations and metadata in the Analysis Services database, while relational OLAP (ROLAP) partitions and dimensions only store metadata in the Analysis Services database. Because the actual contents of an Analysis Services database vary based on the storage mode of each partition, the contents of the backup file also vary. The following table associates the contents of the backup file to the storage mode used by the objects.
Contents of backup file
Multidimensional OLAP (MOLAP) partitions and dimensions
Metadata, source data, and aggregations
HOLAP partitions and dimensions
Metadata and aggregations
ROLAP partitions and dimensions
Backing up an Analysis Services database does not back up the data in any underlying data sources, such as a relational database. Only the contents of the Analysis Services database are backed up.
When you back up an Analysis Services database, you can choose from the following options:
Whether to compress all database backups. The default is to compress backups.
Whether to encrypt the contents of the backup files and require a password before the file can be unencrypted and restored. By default, the backed up data is not encrypted.
For each backup file, the user who runs the backup command must have permission to write to the backup location specified for each file. Also, the user must have one of the following roles: a member of a server role for the Analysis Services instance, or a member of a database role with Full Control (Administrator) permissions on the database to be backed up.
For more information about backing up an Analysis Services database, see Backup Options.
In SQL Server Analysis Services, administrators can restore an Analysis Services database from one or more backup files.
If a backup file is encrypted, you must provide the password specified during backup before you can use that file to restore an Analysis Services database.
During restoration, you have the following options:
You can restore the database using the original database name, or you can specify a new database name.
You can overwrite an existing database. If you choose to overwrite the database, you must expressly specify that you want to overwrite the existing database.
You can choose whether to restore existing security information or skip security membership information.
You can choose to have the restore command change the restoration folder for each partition being restored. Local partitions can be restored to any folder location that is local to the Analysis Services instance to which the database is being restored. Remote partitions can be restored to any folder on any server, other than the local server; remote partitions cannot become local.
For each backup file, the user who runs the restore command must have permission to read from the backup location specified for each file. To restore an Analysis Services database that is not installed on the server, the user must also be a member of the server role for that Analysis Services instance. To overwrite an Analysis Services database, the user must have one of the following roles: a member of the server role for the Analysis Services instance, or a member of a database role with Full Control (Administrator) permissions on the database to be restored.
After restoring an existing database, the user who restored the database might lose access to the restored database. This loss of access can occur if, at the time that the backup was performed, the user was not a member of the server role or was not a member of the database role with Full Control (Administrator) permissions.
For more information about restoring an Analysis Services database, see Restore Options.