[VoiceOps] DST handling
Lee Riemer
lriemer at bestline.net
Thu Nov 5 16:57:59 EST 2009
Another source of skew is multi-processor systems. I'm not sure if it
applies to multi-core, but I would guess it does.
Peter Beckman wrote:
> On Wed, 4 Nov 2009, Colin wrote:
>
>> GMT for the win.
>
> Agreed, though we use UTC. While GMT and UTC are mostly the same,
> UTC is
> based on atomic time and includes leap seconds that are added
> occasionally
> to account for the irregularity in the earth and sun's movements. We
> decided UTC was a more accurate and "official" representation of time.
> GMT is based on the hypothetical average day at Greenwich, which is much
> less scientifically accurate.
>
> Everything in our system is stored as UTC, and we convert on a per-user
> basis when displaying call logs and the like. That way we avoid any
> issues with DST.
>
> I would make all of your CPE devices on UTC as well. It avoids
> confusion
> about what time zone any date/time in your system is on the back end.
> Build the conversion into your front-end systems and reporting on a
> per-customer basis.
>
> You also avoid calls that were really 4 minutes, but get billed as -56
> minutes or 64 minutes for calls during the change from/to DST.
>
> In discussing time, one of my providers avoids syncing their servers to
> the correct time on an ongoing basis (i.e. with ntpd), with the argument
> that if they sync during calls, billing would be wrong. Some of there
> servers therefore skew a LOT, and sometimes their call servers can be
> off
> the real time by _HOURS_ (I suspect this is due to running Asterisk
> on VMs
> which are notoriously bad at keeping time). I've griped about it, but
> they say they only sync the time when there are no calls at midnight,
> which never happens.
>
> Has anyone else been frustrated by the lack of punctuality/analness when
> it comes to making sure clocks are accurate when it comes to call
> records?
>
> Beckman
> ---------------------------------------------------------------------------
>
> Peter Beckman
> Internet Guy
> beckman at angryox.com
> http://www.angryox.com/
> ---------------------------------------------------------------------------
>
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