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A storage pool is a collection of storage volumes. A storage volume is the basic unit of storage, such as allocated space on a disk or a single tape cartridge. The server uses the storage volumes to store backed-up, archived, or space-managed files.
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Storage pool volumes are the physical media that are assigned to a storage pool.
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You can arrange storage pools in a storage hierarchies, which consist of at least one primary storage pool to which a client node backs up, archives, or migrates data. Typically, data is stored initially in a disk storage pool for fast client restores, and then moved to a tape-based storage pool, which is slower to access but which has greater capacity. The location of all data objects is automatically tracked within the server database.
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To maintain free space in primary storage pools, the Tivoli Storage Manager server can automatically migrate data from one primary pool to the next storage pool in the hierarchy. You can control when migration begins and ends, which files to migrate, and whether to run concurrent migration processes.
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When cache is enabled, the migration process leaves behind duplicate copies of files after the server migrates these files to the next storage pool in the storage hierarchy. Using cache can improve the speed with which the server retrieves some files. Consider enabling cache for space-managed files that are frequently accessed by clients.
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Data deduplication is a method for eliminating redundant data in order to reduce the storage that is required to retain the data. Only one instance of the data is retained in a deduplicated storage pool. Other instances of the same data are replaced with a pointer to the retained instance.
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With IBM® Tivoli Storage Manager, you can write data simultaneously to a primary storage pool, copy storage pools, and active-data pools. The simultaneous-write function increases your level of data protection and reduces the amount of time required for storage pool backup.
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With collocation enabled, the server attempts to keep files belonging to a group of client nodes, a single client node, or client file space on a minimal number of sequential-access storage volumes. Collocation reduces the number of volume mounts required when users restore, retrieve, or recall a large number of files from the storage pool. Collocation thus reduces the amount of time required for these operations.
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Space on a sequential-access storage volume becomes reclaimable as files expire or are deleted from the volume. Reclamation processing involves consolidating the remaining data from many sequential-access volumes onto fewer new sequential-access volumes.
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Three default random-access disk storage pools are provided at installation. You can add space to these storage pools by adding volumes, or you can define additional storage pools.
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Monitor your storage pools and volumes to determine space requirements, the status of data migration from one to storage pool to the next storage pool in the storage hierarchy, and the use of disk space by cached copies of files that have been migrated to the next storage pool.
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You might need to move data in some situations, for example, when you need to salvage readable data from a damaged volume. To move data (files) from one volume to another volume in the same or a different storage pool, use the MOVE DATA command. The volumes can be on-site volumes or off-site volumes.
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You can move data located in a sequential-access storage pool for one or more nodes, or for a single node with selected file spaces, using the MOVE NODEDATA command. The data can be located in either a primary storage pool, copy storage pool, or active-data pool.
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When distributing policy using enterprise configuration, you might need to rename a storage pool. Renaming a storage pool can require changing the destination storage pool in copy groups and management classes.
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Use a copy storage pool or an active-data pools to back up one or more primary storage pools. When defining copy storage pools or active-data pools, you can take advantage of various Tivoli Storage Managerfunctions by specifying certain properties.
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Before deleting a storage pool, you need to take certain precautions to prevent data loss and to ensure uninterrupted storage operations.
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You can delete empty storage pool volumes or volumes that contain data from primary storage pools, copy storage pools, or active-data pools. You can also delete the client files that those volumes contain.
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