When you review and analyze performance data, the actual local
time of the collection can be significant.
For example, you may need to be sure which data was collected during the
busiest period of the day so that it represents the heaviest workload experienced
by the system under review. If some of the systems from which you collect
performance data are located in different time zones, you should be aware
of these considerations:
- When you start Collection Services for a system group, you start Collection
Services at the same time on all systems in the group. Any differences in
system time and date settings due to some systems being located in different
time zones are not taken into account.
- If you start Collection Services with the Management Central scheduler,
the time at which the scheduler starts the task is based on the system time
and date of your central system in Management Central.
- The management collection objects for each endpoint system reflect start
and end times based on the QTIME and QUTCOFFSET (coordinated universal time
offset) system values of that endpoint system and your central system. If
the endpoint system is in a different time zone from your central system,
and these system values are correctly set on both systems, the start and end
times reported for collection objects are the actual times on the endpoint
system. In other words, the start and end times reflect the value of QTIME
on the endpoint system as it was at the actual point in time when those events
occurred.
- The scheduling of a performance collection can cross a boundary from standard
time to daylight saving time or from daylight saving time to standard time.
If so, this time difference should be taken into account when scheduling the
start time. Otherwise, the actual start and end times can be an hour later
or earlier than expected. In addition, the reported start and end times for
management collection objects are affected by this difference unless the QUTCOFFSET
system value is adjusted each time the change to and from daylight saving
time takes effect.