IBM SC32-0129-00 LAN-free Client Data Backup Scenario

The storage agent communicates with the server to obtain and store database

information and to coordinate device and volume access. The server and client

coordinate and negotiate data access through the SAN. The client will use the

storage agent for operations where appropriate. For example, if a SAN path is

defined, the client (by means of the storage agent) transfers data on that path. If a

failure occurs on the SAN path, failover occurs and the client uses its LAN

connection to the Tivoli Storage Manager server and moves the client data over the

LAN.

There are cases when the storage agent can send the data directly to the server

using the LAN control paths between the storage agent and the server. An example

of this would be a LAN-free storage pool that is updated to read-only after the

client connects to the server and obtains its initial policy information. The storage

agent, instead of failing the operation, will send the data to the server, and,

providing that the storage hierarchy is configured so that the next storage pool

destination is available, the server will handle the operation. You can also prevent

data from transferring over the LAN by specifying the Tivoli Storage Manager

server parameters DATAREADPATH and DATAWRITEPATH with the REGISTER

NODE or UPDATE NODE commands for the desired node. These settings can be

reviewed by issuing the following command on the server for this node:

query node node_name format=detailed

Tivoli Storage Manager supports SAN-attached device sharing in one of the

following ways:

v Tivoli Storage Manager native library management support consisting of a

library manager and library clients or just a library manager. See “ACSLS, SCSI

and 349X Tape Library Sharing” on page 6 for details regarding libraries.

v Shared disk storage using a FILE library and the integration of Tivoli SANergy,

IBM TotalStorage SAN File System or other supported file-sharing software. For

current information about supported file-sharing software, see

www.ibm.com/software/sysmgmt/products/

support/IBMTivoliStorageManager.html.

v External libraries as defined in the Administrator’s Guide in the appendix,

″External Media Management Interface Description.″

For additional information about these configurations, see “Types of

Environments” on page 5.

LAN-free Client Data Backup Scenario

The following outlines a typical backup scenario for a Tivoli Storage Manager

client that uses SAN data movement:

1. The client begins a backup operation. The server reports policy information to

the client, including whether a destination is LAN-free. As the client assigns

policy settings for files during backup processing, it sends the data LAN-free

when the destination for that policy is LAN-free enabled.

A storage pool is a LAN-free destination when the storage pool uses a device

shared on a SAN. That device must also have a defined path between the

device and the storage agent.

2. The storage agent receives data for those files backed up by the client and

assigned to policy settings that use a LAN-free enabled storage pool. The

storage agent sends a request for a volume mount to the library manager

server. In the external library case, the storage agent contacts the external

library manager, using the provided path to the executable.