Data transport to storage across networks

The Tivoli® Storage Manager environment provides ways to securely move data to storage across various types of networks and configurations.

Network configurations for storage devices

Tivoli Storage Manager provides methods for configuring clients and servers on a local area network (LAN), on a storage area network (SAN), LAN-free data movement, and as network-attached storage.

Data backup operations over a LAN

Figure 1 shows the data path for Tivoli Storage Manager backup operations over a LAN.

Figure 1. Tivoli Storage Manager backup operations over a LAN

Illustration shows movement of data on a LAN in a Tivoli Storage Manager configuration

In a LAN configuration, one or more tape libraries are associated with a single Tivoli Storage Manager server. In this type of configuration, client data, electronic mail, terminal connection, application program, and device control information must all be handled by the same network. Device control information and client backup and restore data flow across the LAN.

Data backup operations over a SAN

Figure 2 shows the data path for Tivoli Storage Manager backup operations over a SAN.

Figure 2. Tivoli Storage Manager backup operations over a SAN

Illustration shows movement of data on a SAN in a Tivoli Storage Manager configuration

A SAN is a dedicated storage network that can improve system performance. On a SAN, you can consolidate storage and relieve the distance, scalability, and bandwidth limitations of LANs and wide area networks (WANs). By using Tivoli Storage Manager in a SAN, you can take advantage of the following functions:

Share storage devices among multiple Tivoli Storage Manager servers. Devices that use the GENERICTAPE device type are not included.
Move client data directly to storage devices by configuring a storage agent on the client system.
Share tape drives and libraries that are supported by the Tivoli Storage Manager server.
Consolidate multiple clients under a single client node name in a General Parallel File System (GPFS cluster.

LAN-free data movement

LAN-free data movement requires the installation of a storage agent on the client system. Through the storage agent, the client can directly back up and restore data to a tape library or shared file system such as GPFS. The Tivoli Storage Manager server maintains the server database and recovery log, and acts as the library manager to control device operations. The storage agent on the client handles the data transfer to the device on the SAN. This implementation frees bandwidth on the LAN that would otherwise be used for client data movement.

Network-attached storage

Network-attached storage (NAS) file servers are dedicated storage servers whose operating systems are optimized for file-serving functions. NAS file servers typically interact with Tivoli Storage Manager through industry-standard network protocols, such as network data management protocol (NDMP) or as primary storage for FILE device storage pools and directory-container storage pools. Tivoli Storage Manager provides the following basic types of configurations that use NDMP for backing up and managing NAS file servers:

Tivoli Storage Manager backs up a NAS file server to a library device that is directly attached to the NAS file server. The NAS file server, which can be remote from the Tivoli Storage Manager server, transfers backup data directly to a drive in a SCSI-attached tape library. Data is stored in NDMP-formatted storage pools, which can be backed up to storage media that can be moved offsite for protection in case of an onsite disaster.
Tivoli Storage Manager backs up a NAS file server to a Tivoli Storage Manager storage-pool hierarchy. In this type of configuration, you can store NAS data directly to disk, either random access or sequential access, and then migrate the data to tape. Data can also be backed up to storage media that can be moved offsite. The advantage of this type of configuration is that you have all of the data management features associated with a storage pool hierarchy.
The Tivoli Storage Manager client reads the data from the NAS system and sends the data to the server to be stored.

Storage management

You manage the devices and media that are used to store client data through the Tivoli Storage Manager server. The server integrates storage management with the policies that you define for managing client data in the following areas:

Device support for server storage: With Tivoli Storage Manager, you can use directly-attached devices and network-attached devices for server storage. Tivoli Storage Manager represents physical storage devices and media with administrator-defined storage objects.
Data migration through the storage hierarchy: For primary storage pools other than directory-container storage pools, you can organize the storage pools into one or more hierarchical structures. This storage hierarchy provides flexibility in a number of ways. For example, you can set a policy to back up data to disks for faster backup operations. The Tivoli Storage Manager server can then automatically migrate data from disk to tape.
Removal of expired data: The policy that you define controls when client data automatically expires from the Tivoli Storage Manager server. To remove data that is eligible for expiration, a server expiration process marks data as expired and deletes metadata for the expired data from the database. The space that is occupied by the expired data is then available for new data. You can control the frequency of the expiration process by using a server option.
Media reuse by reclamation: As server policies automatically expire data, the media where the data is stored accumulates unused space. For storage media other than directory-container storage pools or random disk storage pools, the Tivoli Storage Manager server implements reclamation, a process that frees media for reuse without traditional tape rotation. Reclamation automatically defragments media by consolidating unexpired data onto other media when the free space on media reaches a defined level. The reclaimed media can then be used again by the server. Reclamation allows media to be automatically circulated through the storage management process and minimize the number of media that are required.

Consolidating backed up client data

By grouping the client data that is backed up, you can minimize the number of media mounts required for client recovery. The Tivoli Storage Manager server provides the following methods for grouping client files on storage media other than directory-container storage pools:

Collocating client data

The Tivoli Storage Manager server can collocate client data, in other words client data is stored on a small number of volumes instead of spreading the data across many volumes. Collocation by client minimizes the number of volumes that are required to back up and restore client data. However, collocation by client might increase the number of volume mounts because each client might have a dedicated volume instead of the data from several clients being stored in the same volume.

You can set the server to collocate client data when the data is initially placed in server storage. In a storage hierarchy, you can collocate the data when the server migrates the data from the initial storage pool to the next storage pool in the storage hierarchy. You can collocate by client, by file space per client, or by a group of clients. Your selection depends on the size of the file spaces that are stored and restore requirements.

Associating active-data pools with various devices

Active-data pools are useful for fast client restores, reducing the number of onsite or offsite storage volumes, or reducing bandwidth when you copy or restore files that are vaulted electronically in a remote location. Active-data pools that use removable media, such as tape, offer similar benefits. Although tape devices must be mounted, the server does not have to position past inactive files. However, the primary benefit of using removable media in active-data pools is that the number of volumes that are used for onsite and offsite storage is reduced. If you store data to a remote location, you can minimize the amount of data that must be transferred by copying and restoring only active data.

Creating a backup set

A backup set contains all of the active backed-up files that exist for that client in server storage. The backup set is portable and is retained for the time that you specify. A backup set is in addition to the backups that are already stored and requires additional media

Moving data for a client node

You can consolidate data for a client node by moving the data within server storage. You can move a backup set to different media, where the backup set is retained until the time that you specify. Consolidating data can help to improve efficiency during client restore or retrieve operations.