Installation guide

Managing MTBF Statistics
HP-UX version 11.00.03 Administering Fault Tolerant Hardware 5-31
NOTE
Clearing the MTBF does not bring the device back into service
automatically.
If the device that you cleared is in the ERROR state, you must correct the state using
the ftsmaint reset and enable commands. (See “Correcting the Error State”
for more information.)
Changing the MTBF Threshold
The MTBF threshold is expressed in seconds. If a device’s MTBF falls beneath this
threshold, the system takes the device out of service and changes the device state
to ERROR. If you change the MTBF threshold for a device, the device is not affected
until another failure occurs. For example:
■ If you increase the threshold for a device that is currently in ERROR, you must
enable the device so that it can return to service. The system will not change
the state of the device automatically.
■ If the device’s actual MTBF is less than the new threshold (meaning that
failures occur more often than the threshold allows) and the device in the
CLAIMED state, the system will not recalculate MTBF and take the device out
of service until another failure occurs.
You can change the MTBF threshold for a device. To do so, enter
ftsmaint threshold numsecs hw_path
numsecs is the threshold value in seconds and hw_path is the hardware path of
the device.
Configuring the Minimum Number of Samples
You can set a minimum number of faults required to calculate the MTBF for a
hardware device. (The default minimum fault limit is 6.) For example, if you set
the minimum fault limit to 3, the system requires that at least three failures have
occurred since the last time the statistics were cleared before it can calculate MTBF
for the device. When the system has stored the times of three or more failures for
the device, it uses the times between each failure to calculate MTBF. To set the
minimum fault number, enter
ftsmaint numsamp min_samples hw_path
min_samples is a number from 0 to 6 indicating the minimum number of faults
and hw_path is the hardware path of the device.