TMF Supplement for Large Audit Files (G06.24+)

TMF Reference Manual
HP NonStop TMF Supplement for Large Audit-Trail Files—527391-001
5-7
ADD AUDITTRAIL (Pages 3-14 through 3-19)
specific audit trail, the ATFORMAT value entered through the ALTER TMF
command applies to your entire TMF configuration.).
FILESPERVOLUME Option Considerations
TMF uses the FILESPERVOLUME value to preallocate the number of files in the
active-audit trail that reside on each volume; if they cannot all be allocated, the ADD
AUDITTRAIL command fails. You can change the FILESPERVOLUME value by using
the ALTER AUDITTRAIL command, whether TMF is started or not.
TMF calculates disk extent size on the basis of 16 extents per file, with all extents (both
primary and secondary) being the same size.
OVERFLOWVOL and OVERFLOWTHRESHOLD Option
Considerations
Overflow-audit volumes are used to store files when the active-audit trail becomes too
full. At this point, the oldest audit-trail files are copied to the overflow volumes so that
the space occupied by these audit-trail files can be reused. In the OVERFLOWVOLS
parameter, you can specify the overflow-audit volumes you want TMF to use for this
purpose. In the OVERFLOWTHRESHOLD parameter, you can specify the capacity
level of the active-audit trail that will trigger overflow copying. For example, if you want
overflow copying to begin when 95% of the available audit trail space has been used,
set OVERFLOWTHRESHOLD to 95. The time it takes to reach the overflow threshold
depends on the audit generation rate and the total audit trail capacity.
Once overflow copying begins, it continues until the capacity used falls below the
threshold, even though space subsequently becomes available on the active-audit
volume. When they are no longer needed, overflow files are automatically purged by
TMF.
When audit-trail overflow is triggered, TMF selects the overflow volume from among
those in the overflow volume list for the audit trail. If the overflowing audit-trail file
resides on an active audit volume that is also configured as an overflow volume for that
audit trail, TMF tries to optimize overflow processing by using that same volume: TMF
just renames the overflowing file and preallocates a new audit-trail file. This same-
volume optimization greatly enhances overflow performance by eliminating the need to
copy the audit-trail file to another volume.
However, if TMF cannot perform same-volume optimization, it then searches the
overflow volume list serially to select an overflow volume, and copies the audit-trail file
to that volume.
Note. You should ensure that enough disk space exists to accommodate files of the size
specified in FILESIZE and the number specified in FILESPERVOLUME. If there is insufficient
space on disk to create a new file of the latest configured FILESIZE, TMF simply renames the
existing file even though it may be of improper size or format, and keeps the configuration in a
transition state; in this state, files of different sizes continue to exist.