Tunable Kernel Parameters

Accounting Subsystem
Overview of Accounting Parameters
Chapter 2
17
Overview of Accounting Parameters
When activated by the system administrator, the process accounting subsystem
maintains log files for storing information about system and user processes. These files
can become large, reducing available space for other files on the file system where they
reside.
If process accounting is running, the system suspends process accounting whenever the
available space on the file system where the accounting files reside falls below a certain
threshold. The threshold is defined as the signed, arithmetic sum of the acctsuspend
kernel parameter value at system boot time and the minfree file system parameter
value that was defined during file system creation. (See “How to Determine Value of
minfree” on page 19.) When process accounting is suspended, the system issues the
message:
Accounting suspended
and accounting remains suspended until enough free space becomes available to resume.
The resume threshold value is defined by the signed, arithmetic sum of the acctresume
kernel parameter and the minfree file system parameter. To prevent suspend-resume
conflicts, acctresume must have a value greater than acctsuspend.
When sufficient file system space becomes available and accounting resumes, the system
issues the message:
Accounting resumed
For more information about selecting values for acctsuspend and acctresume, see
“Specifying a Threshold Value” on page 18.
Suspend Accounting Threshold
The suspend accounting threshold can be set to any value from zero to 100 percent of the
usable file system size. Any value for acctsuspend which, when added to minfree,
produces a zero or negative result, sets the suspend threshold at 0 percent, allowing
accounting files to overwrite the entire reserved minimum free space without being
suspended.
Resume Accounting Threshold
The resume accounting threshold also can be set to any value from zero to 100 percent of
the usable file system size. If the signed, arithmetic sum of the acctresume value at
system boot time plus minfree is 100 or greater, accounting cannot resume until the
system is rebooted, or a startup command is executed from the keyboard (see acctsh
(1M)). In a more practical sense, any value that results in a resume threshold higher
than maximum normal free space on the file system will prevent process accounting
from resuming.