AIX

Hi all
We are currently using AIX 5.3, we reuquire to change the time according to the daylight saving scenario. We are using the internal clock and are not synced with ntp server. Can any one please tell me how to do that without effecting the processes running on the servers?

That depends on your application(s). E.g. databases tend to crash when an operation finishes before it started. That would happen if your server is running ahead of time and you set it back during a DB operation is running. If your server's time is behind real time you may simply
# smitty date
for setting date and time and
# smitty chtz
for setting TZ
If you are unsure change both settings only with your apps stopped.

daylight savings time DOES NOT change the clock running in UTC, which is how the internal clock keeps time. It just changes how the values provided by the clock get translated into human readable form.

This affects log timestamps, etc. It also means that cron entries may run twice - this happens going from DST to standard time. Or may run not at all - this happens going to DST from standard time.

So for example, if you want to change to DST, and you do it on a Sunday at 2:00am
you can check for problem cron entries maybe this way:

Code:

 crontab -l |   perl -lane 'print "@F" if $F[1] =~ m/2/'

Hyphens or other special syntax may cause an early morning job to run with no "2" in the hours field. So the above may need changing. For Fall you need to look for "1"