Potential AIX Daylight Saving Time Problem
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There is a potential problem with AIX display of local time which might occur around the transition to standard time this coming weekend.
If the problem occurs, in most cases the only impact is that AIX displays local time incorrectly for a day or so around the transition to or from daylight savings time. AIX displays standard time when it should display daylight savings time or vice versa. Of course, while local time is being displayed incorrectly, if some local time is provided to an application (eg, changing the AIX system clock, specifying to NetBackup the point in time target for a restore, etc) then the application is likely to use a time which is different than the user intended.
The impact on SAP is more severe because SAP periodically checks to confirm that AIX agrees with it regarding the local time. SAP halts the data base if there is any discrepancy! SAP ZDAT
IBM published a High Impact/Highly Pervasive bulletin back in June, which was misleading because it said, "Date output for the AST/ADT time zones is incorrect." The problem can affect time zones other than AST/ADT. A new bulletin was published today attempting to clarify the nature of the issue. The new bulletin is published on the Bulletins for System p web site (at http
A System p server with the AIX TZ environment variable set to any time zone is potentially exposed to the problem, although the consensus within IBM is that as long as TZ is not set in a way which overrides daylight savings time defaults, no problem will occur. It is not possible to override the DST defaults when the TZ environment variable is set (in /etc/environment) using the smit menus. And since the AIX DST defaults are set to United States DST conventions, most users in the US will not override the defaults and so will not be affected this coming weekend, although it is best to apply the fix identified in the bulletin to be absolutely certain. See the Managing the Time Zone Variable Technote (at http
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