Tivoli Storage Manager for Windows: Administrator's Guide


Overview of Media Management and TSM Policy

As part of managing TSM data, you must choose the type of media on which TSM stores client data. For example, given an environment with an 8MM device and a 4MM device, how do you direct client data to one device or another? The answer is - through TSM policy.

When client nodes are registered, you assign them to policy domains containing various policy objects. These policy objects come with default settings that you can modify if necessary. One of the policy objects within each policy domain is the copy group. The copy group points to a storage object called a storage pool, which is created when devices are configured for TSM. Storage pools contain storage pool volumes, with each volume representing a tape or optical disk. Each storage pool is associated with a device class, which specifies the storage device and type of media associated with the storage pool.

Figure 10 shows the TSM policy and storage pool parameters that can affect media management:

Figure 10. Overview of Media Management and TSM Policy

How TSM Affects Media Use

Numbers in the following text (such as (1)) refer to numbers in Figure 10. The Storage Pool parameters and functions can be specified in the DEFINE STGPOOL and UPDATE STGPOOL commands. 

Policy:

(1) Policy Domain
Policy domains are policy objects that contain other policy objects. The policy objects control the behavior of TSM backups. You assign client nodes to policy domains when you register the nodes with TSM. See Getting Users Started.

(2) Policy Set
Policy sets are policy objects that contain management classes and copy groups. Policy sets allow you to create different sets of policy for different purposes, for example, everyday policy for regular backups and special policy for weekends, end-of-year, or, holidays. See Overview: Changing Policy.

(3) Management Class
Management classes are policy objects that allow users to specify how copies of client data are backed up, archived, or both. For space-managed data, the management class specifies how client files are migrated to storage pools. See Chapter 13, Implementing Policies for Client Data.

(4) Copy Group
Copy groups are policy objects that point to storage pools. Storage pools contain volumes, which represent the media on which client data is stored. Storage pools are also the constructs used to associate client data with particular storage devices. See Defining and Updating a Backup Copy Group.

Storage Pool:

(5) Collocation
Collocation is a function that allows you to group client data together on volumes. Collocation provides faster data recovery at the cost of additional backup overhead. See Keeping a Client's Files Together: Collocation.

(6) Reclamation
Reclamation is a function that assists in setting up a media rotation because it allows you to reclaim valid data and to reuse physical media. See Reclaiming Space in Sequential Access Storage Pools.

(7) Maxscratch
Maxscratch is a parameter that specifies whether the volumes in a storage pool are scratch volumes or private volumes and it determines the number of scratch volumes in the pool.

(8) Reuse Delay
Reuse delay is a parameter that sets the amount of time that must elapse before an empty volume can be rewritten.

For more information, see Chapter 13, Implementing Policies for Client Data and Chapter 9, Managing Storage Pools and Volumes.


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