The SQLSTART EXEC issues these CMS FILEDEF commands for the application server:
FILEDEF ARIARCH TAP1 SL (BLKSIZE 4096 NOCHANGE PERM FILEDEF ARITRAC TAP2 SL (BLKSIZE 4096 NOCHANGE PERM FILEDEF ARILARC TAP3 SL (BLKSIZE 4096 NOCHANGE PERM |
The application server uses them for database archiving, tracing, and log archiving. Database archiving is described in Archiving the Database. Tracing is described in ***. Log archiving is described in Archiving the Log.
You can use the BLKSIZE option of the CMS FILEDEF command to override the block size for:
| Note: | The FILEDEF command must be issued in CMS mode, prior to the startup of the application server. A 28 kilobyte block size is used for log archive and database archive file input; you cannot override this value. |
You can specify any output block size from 4 kilobytes to 28 kilobytes in multiples of 4 kilobytes. You must do this before starting the application server by specifying a new BLKSIZE option that will override the ARIARCH and ARILARC FILEDEF commands. For example, you can enter a CMS command similar to this:
FILEDEF ARIARCH TAP1 SL (BLKSIZE 28672 CHANGE PERM |
In the above diagram, the block size is 28 kilobytes (28 672 bytes).
You can use the ALT option of the CMS FILEDEF command to specify an alternative tape drive virtual device number. You can use it, for example, if you do a log or database archive that uses multiple tape volumes. If you specify an alternative tape drive address by overriding the FILEDEF command, the archive switches automatically to the other tape drive when the end of the tape is reached.
To specify an alternative tape drive with the FILEDEF command for the database archive file, enter the following command:
FILEDEF ARIARCH TAP1 SL (ALT cuu |
In the above example, cuu represents the virtual device address of the alternative tape drive. For more information, refer to the VM/ESA: CMS Command Reference.
If you override the FILEDEF commands when running a program in single user mode, specify the PERM option on your FILEDEF. You can omit the PERM option if the program is in Assembler language. For all other languages, you must specify the PERM option.
The DB2 Server for VM System Administration describes reasons you may want to enter FILEDEF commands for the application server.