[asterisk-users] hardware clock drift and CDR

[Vieri]

Hi,

I've noticed that one of my new servers (new mobo) if drifting slowly backwards in time (in aprox. 24 hours, system time drifts back 5 minutes).

I have an ntpd process which is supposed to sync with a lan time server but it's not quite working. So I'm launching a manual ntpdate or ntp-client once an hour and that seems to work.

However, suppose I update system time at every hour and it sets +1 minute (due to a -1 minute drift). Suppose a call is dialed at 03:58 and lasts 4 "real" minutes. According to the updated system time, the call will have lasted 5 minutes (4+1 drift).

How does Asterisk CDR count the duration/billsec values?
Does it rely on system time ONLY for "call start" or also for "call end"?

What Asterisk-related side-effects should I expect from a drifting clock?

Thanks

Vieri