LAN-based and LAN-free data movement

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You can move data between clients and storage devices that are attached to a local area network (LAN), or to storage devices that are attached to a storage area network (SAN), known as LAN-free data movement.

In a conventional LAN configuration, one or more tape libraries are associated with a single IBM Storage Protect server. LAN-free data movement makes LAN bandwidth available for other uses and decreases the load on the IBM Storage Protect server.

In a LAN configuration, client data, email, terminal connection, application program, and device control information must be handled by the same network. Device control information and client backup and restore data flow across the LAN.

A SAN is a dedicated storage network that can improve system performance.

By using IBM Storage Protect in a SAN, you benefit from the following functions:

Sharing storage devices among multiple IBM Storage Protect servers.
Restriction: A storage device with the GENERICTAPE device type cannot be shared among servers.
Moving IBM Storage Protect client data directly to storage devices (LAN-free data movement) by configuring a storage agent on the client system.

In a SAN, you can share tape drives and libraries that are supported by the IBM Storage Protect server, including most SCSI tape devices.

When IBM Storage Protect servers share a SCSI tape, one server, the library manager, owns and controls the device. The storage agents, along with other IBM Storage Protect servers that share this library are library clients. A library client requests shared library resources, such as drives or media, from the library manager, but uses the resources independently. The library manager coordinates the access to these resources. IBM Storage Protect servers that are defined as library clients use server-to-server communications to contact the library manager and request device service. Data moves over the SAN between each server and the storage device.

Requirement: If you define a library manager server that is shared with the IBM Storage Protect server, the SANDISCOVERY option must be set to ON. By default, this option is set to OFF.

IBM Storage Protect servers use the following features when sharing an automated library:

Partitioning of the volume inventory: The inventory of media volumes in the shared library is partitioned among servers. Either one server owns a particular volume, or the volume is in the global scratch pool. No server owns the scratch pool.
Serialized drive access: Only one server accesses each tape drive at a time. Drive access is serialized. IBM Storage Protect controls drive access so that servers do not dismount other servers' volumes or write to drives where other servers mount their volumes.
Serialized mount access: The library autochanger completes a single mount or dismount operation at a time. The library manager completes all mount operations to provide this serialization.