IBM Tivoli Storage Manager, Version 7.1

Manually redistributing data and reclaiming space after you add directories to the database

If you add directories to the Tivoli® Storage Manager database with the EXTEND DBSPACE command and choose not to redistribute data and reclaim space at the same time, you can complete these tasks later by using DB2® commands.

Before you begin

Restriction: The redistribution process, also known as rebalancing, only works with DB2 version 9.7 or later table spaces, which are created when you format a new Tivoli Storage Manager version 6.2 or later server. If you upgraded or restored your Tivoli Storage Manager server from version 6.1, and you want to rebalance your table spaces, contact IBM® Software Support for instructions.

Redistribution uses considerable resources. Review the following guidelines before you start the procedure:

Run the process when the server is not handling a heavy workload.
To redistribute data to new directories, the storage paths must be able to host the directories and data. Make sure that sufficient disk space is available for the operation.
The time that is required to redistribute data and reclaim space might vary. File system layout, the ratio of new paths to existing storage paths, server hardware, and concurrent operations are all factors in determining the time requirement. Start the process with one small and one medium-sized table space and then try a larger table space. Use your results as a reference to estimate the time that is needed to process remaining table spaces.
Do not interrupt the process. If you try to stop it, for example, by halting the process that is completing the work, you must stop and restart the DB2 server. When the server is restarted, it will go into crash recovery mode, which takes several minutes, after which the process resumes.

Procedure

Complete the following steps to redistribute data and then reclaim space for each table space. For the best performance, rebalance a table space and then reduce the size for that table space. While the size for the first table space is being reduced, you can start rebalancing on the second table space, and so on.

Open the DB2 command line processor and issue the following command:
```
db2 connect to tsmdb1
```
List DB2 table spaces by issuing the following command. To display details about each table space, including the total size of a table space and how many bytes are used in each file system where the table space is located, include show detail.
```
db2 list tablespaces show detail
```
You only need to redistribute data on Database Managed Space (DMS) table spaces. The following example output shows where the table space type is identified:
```
Tablespaces for Current Database

 Tablespace ID            = 0
 Name                     = SYSCATSPACE
 Type                     = Database managed space  <---DMS table space.
 Contents                 = All permanent data. Regular table space.
 State                    = 0x0000
 Detailed explanation:
 Normal
```
Use the list that you obtained in Step 2 to identify each DMS table space. For each DMS table space, issue the following command to start redistribution of data for the first DMS space:
```
db2 alter tablespace tablespace_name rebalance 
```
Monitor the data redistribution progress by issuing the following command:
```
db2list utilities show detail
```
If the rebalance process is running, the command output shows Type = REBALANCE, and also indicates how many extents are moved and how many remain to be moved.
The following example output shows where these details are displayed:
```
ID = 6219
Type = REBALANCE                   <--- Data is being redistributed.
Database Name = AX4
Partition Number = 0
Description = Tablespace ID: 37
Start Time = 04/27/2009 21:37:37.932471
State = Executing
Invocation Type = User
Throttling:
Priority = Unthrottled
Progress Monitoring:
Estimated Percentage Complete = 15
Total Work = 22366 extents         <--- Total extents to be moved.
Completed Work = 3318 extents      <--- Total extents moved.
Start Time = 04/27/2009 21:37
```
The value in the Completed Work field should increase as the redistribution progresses. The db2diag log also records status about the process, including start and complete time and what percentage of the process is complete at a certain time.
After the redistribution process is completed, reduce the size for each table space. During and after the operation, table spaces have a much larger total size because directories are added. Issue the following command:
```
db2 alter tablespace tablespace_name reduce max
```

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