SAT4:30 vs GMT-4

[Julio Porras_1]

I am from VENEZUELA. When I run "/sbin/set_parms timezone" in my new HP-UX 11.11 server, I get a nice menu that tells me to use SAT4:30 for my timezone (according to my country). The problem is I have always used GMT-4 for all my old servers, and there is a BIG time difference between the old ones and the new one that uses SAT4:30. For example, when I copy a file between an old and the new server, a time difference of about 8 hours shows up in the copied files.

What is SAT4:30 ?
Why the time difference with GMT-4 ?
What shoud I use ?

Thanks,
Julio.

[Naveej.K.A]

hi julio,

what does /etc/TIMEZONE say??

regds
Naveej

[Kent Ostby]

Everything I could find on the web indicates that venezuela should use GMT-4.

The only documents that I could find in HP's database or on the web were issues where software wouldn't install with a timezone of SAT4:30.

I was surprised at how little there was out on the web regarding this issue.

Best regards,

Kent M. Ostby

[Julio Porras_1]

Well, I changed the time zone to SAT4:30 to avoid inconsistency between servers. This machine is my SAP productive system, so let me know how bad you need to know the contents of that file, because I'll need to reboot if I change the time zone value back to GMT-4.

Right now the file has this in it:

prosap06[root]/etc >more TIMEZONE
TZ=SAT4:00
export TZ

[Bill Hassell]

/etc/TIMEZONE can be changed without a reboot. It is normally read when a user logs in and is also read by some applications as well as during startup. NOTE: all your files are timestamped correctly. HP-UX only uses GMT (UTC or Zulu) time and the $TZ variable translates this time to your local setting. TZ is set as you login by simple executing the /etc/TIMEZONE file. Do this:

export TZ=GMT-4

and now look at your files. The timestamps will reflect the correct time. This sets the TZ value and time is translated from GMT to GMT-4. Now if your database was started with TZ=SAT4:30, then the database will be recording time based on the current TZ value. You'll have to stop the database and either change TZ for the database environment or reboot so the database starts with the correct TZ value.

[Julio Porras_1]

What is SAT4:30 ?
And why HP-UX ( "/sbin/set_parms timezone" )encourages me to use that, instead of GMT-4 ?

[Bill Hassell]

SAT-4:30 is undefined in /usr/lib/tztab file and normally, all timezone rules are defined in this file. SAT isn't there at all so it's a guess as to what the abbreviation means. According to the man pages for tztab and environ, this is what it means:

SAT = an arbitrary name for the timezone
-4:30 = number of hours:mins to add to the local time to arrive at GMT or UTC time. In this case, 4.5 hours must be subtracted (-4:30 means add a negative 4.5 hours) to get UTC.

Now why SAT-4:30 exists in the set_parms program, I don't know. However, timezones are defined by your government, not HP. If the correct time of day at your location is 4 hours earlier than GMT, then GMT-4 is the correct value to use. In the tztab file, Venezuela is not defined. That's OK because tztab is designed to provide varied rules about timezones and daylight saving rules.

So you can use GMT-4 (and edit the value in /etc/TIMEZONE) but if your local area has daylight saving rules (one hour forward or backward each year), then you'll neeed to add the rules to tztab.