AIX Tip of the Week

Check Your Time Zone Setting for Possible Defect

Audience: All

Date: October 15, 2003

Last year a defect prevented some AIX systems from implementing the shift from "daylight savings" to "standard" time. This caused considerable consternation among sysadmins, especially those that changed the system clock when they discovered it was apparently set wrong.

With the time change two weeks away, it would be a good idea to verify that your system does not have this problem.

The defect causes two commas to be appended to the TZ environment variable when it is set via smit chtz For example, the "echo $TZ" command displays "CST6CDT,,". Check the TZ variable in /etc/environment. If it is corrupted, install the appropriate APAR

AIX V4.3.3	IY34798		SMITTY CHTZ APPENDING 2 COMMAS AFTER TZ
AIX V5.1	IY34203		SMITTY CHTZ APPENDING 2 COMMAS AFTER TZ
AIX V5.2	IY35629		SMITTY CHTZ APPENDING 2 COMMAS AFTER TZ

and then run the command "smit chtz". Once TZ is set properly, refresh the cron daemon, and restart applications that are sensitive (like cron) to the current time. (The most cautious approach is to reboot the system, since it is very difficult to identify every process which is sensitive to the current time and which is still running with the old setting of $TZ.)

PS Thanks to Steve Pittman for this tip!


Bruce Spencer,
baspence@us.ibm.com