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As your requirements change, you can increase or decrease the sizes of the database and recovery log. You can automate part of the process of increasing the sizes, or you can perform all the steps manually. See Automating the Increase of the Database or Recovery Log or Manually Increasing the Database or Recovery Log.
Attention: Do not change the size of an allocated database or recovery log volume after it has been defined. If you change the size of a volume, Tivoli Storage Manager may not initialize correctly, and data may be lost.
You can automate the process of determining when the sizes of the database and recovery log must be increased. With a DEFINE SPACETRIGGER command, you can specify the following:
For example, assume that you have a 100GB database and a 3GB recovery log. You want to increase the database size by 25 percent when 85 percent is in use, but not to more than 200GB. You also want to increase the recovery log size by 30 percent when 75 percent is in use, but not to more than 5GB. Issue the following commands:
define spacetrigger db fullpct=85 spaceexpansion=25 maximumsize=200000 define spacetrigger log fullpct=75 spaceexpansion=30 maximumsize=50000
The server then monitors the database or recovery log and, if the utilization level is reached, does the following:
Notes:
If the log mode is set to ROLLFORWARD and either the recovery log is too small or the database backup trigger is set too high, the recovery log could run out of space before database operations complete. If this happens, you may need to stop the server without enough recovery log space to restart the server. In some cases, the server halts itself.
To restart the server, first format a new volume. Then use the DSMSERV EXTEND LOG command to extend the size of the recovery log. For example, after formatting a 21MB volume named new.reclog, extend the recovery log by issuing the following command:
dsmserv extend log new.reclog 20
After the server is running, you can do the following:
To add space to the database or recovery log, do the following:
To allocate database and recovery log volumes, use ANRFMT or ANRFMT2. If you have set the space trigger and received message ANR4413I or ANR4414I, use the value from the message.
The maximum size of the recovery log is 13GB, and the maximum size of the database is 530GB. If you allocate a volume that would cause the recovery log or database to exceed these sizes, the subsequent DEFINE DBVOLUME or DEFINE LOGVOLUME command for the volume fails.
Notes:
If you already have a number of small volumes and want to consolidate the space into one large volume, see Decreasing the Size of the Database or Recovery Log.
To define a database volume named VOL5, enter:
define dbvolume vol5
When defined, the volume becomes a part of the logical view of the database. Thus, Tivoli Storage Manager sees a single logical database volume, which is now composed of five physical volumes. Because 1MB from VOL5 is used for overhead process, 100MB is added to the database to increase the available space to 196MB. However, the assigned capacity remains at 96MB, and the space cannot be used until the capacity is extended (see Step 3: Extending the Capacity of the Database or Recovery Log).
After you define your volumes, you can verify the change by querying the database or recovery log. For example, to query the database, enter:
query db
The server displays a report, like this:
+--------------------------------------------------------------------------------+ |Available Assigned Maximum Maximum Page Total Used %Util Max. | | Space Capacity Extension Reduction Size Pages Pages %Util | | (MB) (MB) (MB) (MB) (bytes) | |--------- -------- --------- --------- ------- --------- --------- ----- ----- | | 196 96 100 92 4,096 24,576 86 0.3 0.3 | +--------------------------------------------------------------------------------+
The value in the Maximum Extension field should equal the available space of the new volume. In this example, a 101MB volume was allocated. This report shows that the available space has increased by 100MB; the assigned capacity is unchanged at 96MB; and the maximum extension is 100MB. Figure 48 illustrates these changes.
Figure 48. Adding Volumes Increases Available Space
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You can issue the QUERY DBVOLUME and QUERY LOGVOLUME commands to display information about the physical volumes that make up the database and recovery log.
The database and recovery log are extended in 4MB increments. If you do not specify the extension in 4MB increments, the server rounds up to the next 4MB partition. For example, if you specify 1MB, the server extends the capacity by 4MB.
To increase the capacity of the database by 100MB, enter:
extend db 100
After the database has been extended, the available space and assigned capacity are both equal to 196MB, as shown in Figure 49.
Figure 49. Extending the Capacity of the Database
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You can query the database or recovery log (QUERY DB and QUERY LOG commands) to verify their assigned capacities. The server would display a report, like this:
+--------------------------------------------------------------------------------+ |Available Assigned Maximum Maximum Page Total Used %Util Max. | | Space Capacity Extension Reduction Size Pages Pages %Util | | (MB) (MB) (MB) (MB) (bytes) | |--------- -------- --------- --------- ------- --------- --------- ----- ----- | | 196 196 0 192 4,096 50,176 111 0.2 0.2 | +--------------------------------------------------------------------------------+