-SET ARCHIVE (DB2)

The DB2® command SET ARCHIVE sets the maximum number of tape units for the archive log. It also sets the maximum deallocation time of tape units for the archive log.

This command overrides the values that are specified during installation or in a previous invocation of the SET ARCHIVE command. The changes that SET ARCHIVE makes are temporary; at restart, DB2 again uses the values that are set during installation.

Abbreviation: -SET ARC

Environment

This command can be issued from a z/OS® console, a DSN session under TSO, a DB2I panel (DB2 COMMANDS), an IMS™ or CICS® terminal, or a program using the instrumentation facility interface (IFI).

Data sharing scope: Member

Authorization

To execute this command, you must use a privilege set of the process that includes one of the following privileges or authorities:

ARCHIVE privilege
SYSOPR authority
SYSCTRL authority
SYSADM authority

DB2 commands that are issued from a logged-on z/OS console or TSO SDSF can be checked by DB2 authorization using primary and secondary authorization IDs.

Syntax

>>-SET ARCHIVE-------------------------------------------------->

>--+-+-----------------+-+-----------------------------------+-+-><
   | '-COUNT-(integer)-' '-TIME(-+-minutes--+----------+-+-)-' |   
   |                             |          '-,seconds-' |     |   
   |                             +-,seconds--------------+     |   
   |                             +-1440------------------+     |   
   |                             '-NOLIMIT---------------'     |   
   '-DEFAULT---------------------------------------------------'

Option descriptions

The following options override the READ TAPE UNITS(COUNT) and DEALLC PERIOD TIME subsystem parameters that are specified during installation.

COUNT( integer )

Specifies the maximum number of tape units that can be dedicated to reading archive logs. This value affects the number of concurrent reads that are allowed for unique archive data sets that reside on tapes.

integer can range from 1 to 99.

If the number that you specify is greater than the current specification, the maximum number of tape units allowable for reading archive logs increases.
If the number that you specify is less than the current specification, tape units that are not being used are immediately deallocated to adjust to the new COUNT value. Active (or premounted) tape units remain allocated; only tape units that are inactive are candidates for deallocation because of a lowered COUNT value.

TIME

Specifies the length of time during which an allocated archive read tape unit is allowed to remain unused before it is deallocated.

( minutes ): Specifies the maximum number of minutes.
minutes must be an integer between 0 and 1439.
( seconds ): Specifies the maximum number of seconds.
seconds must be an integer between 1 and 59.
(NOLIMIT) or (1440): Indicates that the tape unit will never be deallocated. Specifying TIME(1440) is equivalent to TIME(NOLIMIT). The seconds specification is not allowed when you specify that TIME is 1440.

DEFAULT

Resets the COUNT and TIME parameters back to the values that were specified during DB2 installation.

Usage notes

Archive tape reading performance: To achieve the best performance for reading archive tapes, specify the maximum values that are allowed (within system constraints) for both the COUNT and TIME options.

IEF238D "REPLY DEVICE NAME OR CANCEL" message: Replying "CANCEL" to this message resets the COUNT value to the current number of tape units. For example, if the current COUNT value is 10, but you reply "CANCEL" to the request for the seventh tape unit, the COUNT value is reset to 6.

Delaying tape deallocation in a data sharing environment: When you submit a recover job on a member of a data sharing group that requires a tape unit that must remain unused for a certain length of time before it is deallocated, the archive tape is not available to any other member of the group until the tape is deallocated. Unless all recover jobs will be submitted from the same member, you might not want to use the COUNT option and ensure that field DEALLOC PERIOD on installation panel DSNTIPA has a value of 0.

Output

The response from this command includes any of the messages from DSNJ334I through DSNJ337I.

Examples

Example 1: Allocate two tape units that can remain unused for 30 seconds before they are deallocated.

-SET ARCHIVE COUNT(2) TIME(,30)

Example 2: Allocate four tape units that can remain unused for 2 minutes before they are deallocated.

-SET ARCHIVE COUNT(4) TIME(2)

Example 3: Allocate one tape unit that is never deallocated.

-SET ARCHIVE COUNT(1) TIME(1440)