Re: dom0 and timed

["Sarton O'Brien" <bsd-xen%roguewrt.org@localhost>]

Daniel Hagerty wrote:
>  > Forgive me but does this relate more to the actual time keeping? The
>  > main problem I saw was that at some point, ntpd would stop servicing
>  > clients and would require a restart. I have a feeling it related to the
>
>     The PLL issue is addressed at "ntp is causing kernel panics".


Oh, sorry, I didn't link the two. I'll disable the kernel option.


>  > addition and removal of vifs within a dom0. In the end, that may just be
>
>     Very likely.  I don't know what NTP's current story is for dealing
> with this better, but historically ntp has done strange things in the
> face of interfaces coming and going.  The -I option might help, but
> probably not.  I'd like to think they have a story for this common
> problem, but I don't know what it is.
>
>     This particular failure mode of the udel ntpd has long been a
> favorite advertising point for openbsd's ntp implementation.
> Personally, if I couldn't get udel ntp working in a situation, I'd try
> openbsd's ntp before going with timed.


I seem to remember trying -I in the past with little success but I'll 
double check.


>     Timed's biggest single issue is that it merely aims to keep clocks
> synchronized.  This is a very different goal from ensuring that clocks
> have the correct time, and tick one second per second.


So ntpd is a time keeper/monitor and timed is a clock synchroniser ... 
gotchya.


>     NTP will certainly beat timed in accuracy or whatnot, but really
> the big difference that any normal person will care about is correct
> time vs synchronized time.
>
>
>     Anyway, I only say anything because you said "timed" and also
> something about "timed and ntp", where the latter is certainly a
> "don't do that".  Pick one.


OK, I understand now ... so assuming timed is still relevant ... 
wouldn't you need a master time source using ntpd to synchronise time 
with and wouldn't that source require a master timed service so that 
clients can synchronise an accurate time?

There seems to be a bit of a 'gothcya' when it comes to picking one :S

Thanks again,

Sarton