1.2 SMS Components

In order to achieve full functionality, SMS is implemented as two independent components that provide the following functional abstractions:

SMS components on the backup server and the target servers

The backup process is explained below:

1.2.1 Storage Management Data Requester

The Storage Management Data Requester (SMDR) is the communication module in the SMS architecture. The SMDR defines the API framework, provides remote connectivity, and abstracts the details of any communication between the servers. Thus, SMDR is capable of transferring any target data between the target and backup server. Most backup applications use the API exposed by SMDR to make use of functionality exposed by SMS. For information on configuring SMDR, See Section 3.4, Configuring SMDR.

1.2.2 Target Service Agent (TSA)

The Target Service Agent (TSA) provides an implementation of SMS APIs for a particular target. The TSA provides transparency by abstracting details of the specific service (such as GroupWise or NSS) being backed up. For example, various backup applications use file system TSA to back up and restore NSS file system data and metadata (trustee assignments, namespaces, and file attributes). A TSA understands the target and knows how to scan, read, and write a particular target’s data. Each target needs a TSA.

Table 1-1 Target Services and Their Corresponding Target Service Agents in OES 2 Linux

Target Service

Target Service Agent

NSS file system


Cluster resources


VFS-compliant file systems










  • TSAFS backs up a target server, so it services all file systems (and possibly cluster resources) on a particular target server.

  • GroupWise backup functionality is included with the file system TSA.

    However, the functionality does not provide object level backup, but simply ensures that GroupWise database backups are consistent by freezing the GroupWise database before a regular file system backup. This functionality is not turned on by default. See File System TSA (TSAFS) to turn on this functionality as required.

File System TSA (TSAFS)

The File System TSA (TSAFS) supports all VFS-compliant file systems and NSS. Some of the salient features are:

  • Implements a predictive data caching model that provides improved backup performance.

  • Provides parameters to fine-tune performance.

  • Provides parameters that can be used to fine-tune performance to the specific environment.

  • Ability to interpret OES 2 Linux data streams.

  • Cluster enabled.

  • Multiprocessor enabled.

  • Compatible with the data format used by existing versions of the TSA.

  • Ability to ensure consistency while backing up GroupWise databases.

  • Provides a NetWare emulation mode.

  • Ability to handle data across locales by providing data in UTF-8 format.