Parallel Checkpointing in UNIX
In UNIX, you can checkpoint to a disk or a tape in parallel.
Checkpoint to Disk
To checkpoint a multi-location database to disk in parallel, issue the ckpdb command with the #m flag followed by the number of parallel checkpoints to be run. For example, to save two data locations at a time to the II_CHECKPOINT location, the command is as follows:
ckpdb \#m2 dbname
Checkpoint to Tape
To checkpoint a multi-location database to tape in parallel, in the Checkpoint dialog, specify multiple table devices to be used in the Tape Device edit control. For example, enter the following:
/dev/rmt/0m,/dev/rmt/1m
This saves one location per tape-the first location can be stored on device 0m; the second on device 1M. The third location can be stored on whichever device is finished first. The remaining locations can be stored on the next free device. The operator is prompted to insert a new tape for each location.
When performing parallel checkpointing to tape, keep in mind the following:
• Recovery does not have to be in parallel if a checkpoint was done in parallel.
• Each tape label must include the checkpoint number, database name, and location number.
• Each tape device must be the same medium, that is, all 4mm or all 8mm; mixing is not permitted.
• The maximum number of devices that can be used is limited by the system’s input and output bandwidth.
Last modified date: 11/28/2023