198
IBM Tivoli Storage Manager Implementation Guide
5.4 Defining the database backup trigger
The database backup trigger determines when to back up the Tivoli Storage
Manager database, based on the recovery log utilization. When the recovery log
is in rollforward mode, the potential for it to fill up is much greater than in normal
mode. If the recovery log fills up, it is possible that the server can stall or even
halt unexpectedly. By defining a database backup trigger, when the recovery log
usage reaches the defined percentage, the server database is automatically
backed up. The backup operation clears the cached transactions, clearing the
recovery log.
Use the
define dbbackuptrigger
command to define settings for the database
backup trigger, such as the percentage of the assigned capacity and device
class to be used for automatic database backups. You can also define the
number of incremental database backups that can be run before a full backup
must run. These settings are used only when the recovery log mode is
ROLLFORWARD.
The actual percentage to choose depends on the planning considerations
discussed in Chapter 2, “Implementation planning” on page 15. We recommend
using 75% as a starting point and use the default number of incrementals (six).
Monitor your environment’s activity to make sure that you do not trigger database
backups too frequently, as this creates unnecessary load on the server and
increases tape mount activity. If database backups are triggering too frequently,
consider increasing the recovery log size.
Example 5-7 shows how to set the limit of 75% and run up to six incremental
database backups before a full database backup.
Example 5-7 Setting the database backup trigger
tsm: LOCHNESS_SERVER1>
def dbbackuptrigger devclass=lto2-dc logfullpct=75
numincremental=6 incrdevclass=lto2-dc
ANR2282I Database backup trigger defined and enabled.
tsm: LOCHNESS_SERVER1>
query process
Note: If you are changing the recovery log to rollforward mode, the recovery
log size must be increased. To estimate the new value, reset the cumulative
log consumption statistic using the administrative command
reset
logconsumption
. Monitor the cumulative consumption over a number of days.
Divide the cumulative consumption by the number of days since you reset the
value, to get an average value. A safe size for the log pool is around 30–40%
larger than this figure.
Summary of Contents for E16RMLL-I - Tivoli Storage Manager
Page 2: ......
Page 23: ...Figures xxi 22 6 AIX lab environment 708...
Page 24: ...xxii IBM Tivoli Storage Manager Implementation Guide...
Page 32: ...2 IBM Tivoli Storage Manager Implementation Guide...
Page 44: ...14 IBM Tivoli Storage Manager Implementation Guide...
Page 94: ...64 IBM Tivoli Storage Manager Implementation Guide...
Page 96: ...66 IBM Tivoli Storage Manager Implementation Guide...
Page 126: ...96 IBM Tivoli Storage Manager Implementation Guide...
Page 298: ...268 IBM Tivoli Storage Manager Implementation Guide...
Page 354: ...324 IBM Tivoli Storage Manager Implementation Guide...
Page 356: ...326 IBM Tivoli Storage Manager Implementation Guide...
Page 423: ...Chapter 12 Scheduling 393 Week of Month Expire Never tsm quit...
Page 424: ...394 IBM Tivoli Storage Manager Implementation Guide...
Page 510: ...480 IBM Tivoli Storage Manager Implementation Guide...
Page 552: ...522 IBM Tivoli Storage Manager Implementation Guide...
Page 554: ...524 IBM Tivoli Storage Manager Implementation Guide...
Page 594: ...564 IBM Tivoli Storage Manager Implementation Guide...
Page 612: ...582 IBM Tivoli Storage Manager Implementation Guide...
Page 618: ...588 IBM Tivoli Storage Manager Implementation Guide...
Page 720: ...690 IBM Tivoli Storage Manager Implementation Guide...
Page 752: ...722 IBM Tivoli Storage Manager Implementation Guide...
Page 758: ...728 IBM Tivoli Storage Manager Implementation Guide...
Page 780: ...750 IBM Tivoli Storage Manager Implementation Guide...
Page 802: ...772 IBM Tivoli Storage Manager Implementation Guide...
Page 823: ...Index 793 Z z OS tape management 58 zOS 200...
Page 824: ...794 IBM Tivoli Storage Manager Implementation Guide...
Page 825: ...IBM Tivoli Storage Manager Implementation Guide...
Page 826: ......
Page 827: ......