Time / NTP and TZ

Question

I have a couple of servers that thanks to a quirky SAP installation cannot be allowed to change their time zone on their own.
They have to run on GMT and have the system clock manually changed to and from BST (GMT + 1).
Is there a way of applying a 1 hour offset to a local NTP server?
In other words, have the NTP serving the correct time and then during daylight saving apply a 1 hour offset to the signal NTP server sends out.
The added complication is that this NTP server would be getting it's time from an outside UTC.

Answer 1

andrew9876 wrote:
Thanks Darren, I had a feeling I'd get an answer like that.
The next option is to modify TZ variable but as I understand this cannot be done on the fly as modifying the TZ variable only affects the shell from where TZ was modified and so requires a initd change and reboot.TZ is an environment variable. So any process that can be restared can get a new setting. Of course in some applications (like a corporate database), a reboot may be politically identical to restarting the process.
The last, and most messy option is to run an NTP server on a 1/2 hour 1/2 hour time share. Where we have it recieving NTP info from a Stratum 1 but not sending the time out. Then shut off the reception, add one hour to the system clock and run it for half an hour as a stratum 2 (or 3) NTP server and flip flop between the two states.That's pretty hacky (and if you did do that, please run it at a higher stratum than 2 or 3). Why would you bother syncing externally though? What kind of precision are you requiring for this setup? I worry that the simple act of "adding one hour" could exceed that. If it doesn't, then just watching that the clock isn't too far off by hand may be sufficient rather than swapping things around twice an hour.
Darren