Time Change

[linkfan]

Hi all,

This is my first post on this forum.

I want to prevent of time change on my server (Cent OS 5.4). This can be done by turning off ntpd deamon?

Sorry for my bad english...

Regards,

Linkfan

[Rubberman]

What do you really want to accomplish? Ie, what do you mean by "prevent time change"? The only thing that NTP does is to keep your system clock in sync with international time standards, so you can be assured that the clock is correct (to a few milliseconds at least) continually.

[linkfan]

First of all thx for reply

I just don't want to change time on my server when it's Summer/Winter time (DTS)

Our application is doing it for us

Is it enough to turn off ntpd?

Regards,
Linkfan

[Irithori]

No, turning off ntpd will not prevent summer/winter time change.

And imho it is bad to let the server knowingly have a false time.
Think about timestamps in logs, other daemons, synchronisations..

Perhaps the better approach would be to fix that application.

[Rubberman]

Normally, you set the hardware clock to GMT, and your system timezone settings adjust the perceived clock. That way, all timestamps are correct in absolute terms since they get the system hardware time (GMT) as a numerical value since 0:00:00 am on Jan.1, 1970 before saving it, such as in the access/update timestamps in a directory listing. If you want to bypass this, you can set your hardware clock to local (non-DST) time and disable timezone adjustments altogether. However, that is NOT recommended. As Irithori suggested, it is better to fix the application.

In any case, I do understand your frustration with this. More applications suffer from mis-use of date/time values than just about any other singe item. That's why I always recommend that date/time values be stored as a full date+time value (either system time value or Julian value) and then the application can convert and display it as necessary or desired. That approach also allows one to do easy date arithmetic (did event A occur before event B, or did Joe really work a full 8 hour shift that day) without trying to convert simple time values (Joe started work at 11:00pm and finished up at 7:00 am - do you owe him for an hour of overtime because the clock was set back due to DST changes) when you don't know if daylight saving time was in effect or not. The issues in this sort of situation are endless and I have had to help sort out many clients with this exact problem.