To help keep the size of the file /var/adm/pacct under control, the cron command runs /usr/lib/acct/ckpacct to check the size of the file and the available disk space on the file system.
If the size of the pacct file exceeds 1000 blocks (by default), it runs the turnacct command with argument "switch." The "switch" argument causes turnacct to back up the pacct file (removing any existing backup copy) and start a new, empty pacct file. This means that at any time, no more than 2000 blocks of disk space are taken by pacct file information.
If the amount of free space in the file system falls below 500 blocks, ckpacct automatically turns off process accounting by running the turnacct command with the "off" argument. When at least 500 blocks of disk space are free, accounting is activated again the next time cron runs ckpacct.