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Managing DB2 Recovery Data Sets with SMS 69
Figure 20. Example VSAM Definition of One Active Log
7.3.1 Storage Class
A Storage Class with guaranteed space set to yes, enables the DB2 administrator
to decide the location of the active logs.
• SCDBACTL
7.3.2 Management Class
The following Management Class has been defined for active logs, no SMS
management is required.
• MCDBACTL
7.3.3 Storage Group
The same Storage Groups used for the BSDSs with guaranteed space set to yes,
are also used for the active logs.
• SGDBACTL for several DB2 subsystems
• SGDB2PLG for the DB2P susbsystem
7.3.4 ACS Example
An example of ACS routines to allocate these SMS classes and Storage Groups
for active logs is shown in Appendix B, section B.1, “BSDS and Active Logs” on
page 185.
7.4 Archive Logs
Archive log data sets are DB2 managed backups of the active log data sets.
Archive log data sets are required for any recovery that spans a period of time in
excess of the time covered by the active logs. This is illustrated in Figure 5 on
page 19. Archive log data sets are created automatically by DB2 when an active
log fills up, but they may also be created with the -ARCHIVE command.
Data Organization
Archive Log data sets are physical sequential data sets. Record size is 4096 and
the block size is typically 28672 bytes. The allocation of archive logs is done
dynamically by DB2. The DB2 system administrator can influence this process,
specifying options in the DB2 parameter module (default name = DSNZPARM).
Those parameters are defined on installation panel DSNTIPA. An example
definition is shown in Figure 21 on page 70. On this panel, the DB2 administrator
DEFINE CLUSTER -
( NAME (DB2V610Z.LOGCOPY1.DS01) -
VOLUMES(SBOX09) -
REUSE -
RECORDS(8640) -
LINEAR ) -
DATA -
( NAME (DB2V610Z.LOGCOPY1.DS01.DATA) -
)