Tivoli Storage Manager for Windows Administrator's Guide


Overview of Media Management and TSM Policy

As part of managing TSM data, administrators 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 does an administrator direct client data to one device or another? The answer is - through TSM policy.

When client nodes are registered, administrators assign them to policy domains. Policy domains include other policy objects that are either set to default values or set to administrator-defined values. One of the policy objects within each policy domain points to the copy group. The copy group points to a storage object called a storage pool. Storage pools are created when devices are configured for TSM. Storage pools contain storage pool volumes and each is equivalent to a tape or optical disk. Storage pools are associated with device classes, which determines which device and which type of media is used.

Figure 6 shows the TSM policy and storage pool parameters that can affect media management:

Figure 6. 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 6. 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. Administrators assign client nodes to policy domains when they 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 administrators 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 Changing Policy with the Active Policy Set.

(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 11, Implementing Policies for Client Data.

(4) Copy Group
Copy groups are policy objects that point to storage pools. Storage pools represent the media on which client data is backed up and they are the constructs that tie user data to devices. See Defining and Updating a Backup Copy Group.

Storage Pool:

(5) Collocation
Collocation is a function that allows administrators 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 the administrator 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 11, Implementing Policies for Client Data and Chapter 8, Managing Storage Pools and Volumes.


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