I'm going to set Minpoll and Maxpoll time in my ntpd.conf for my NTP
internal server (MASTER) which must be synchronized to external
servers (stratum 1 or 2), because I think 64s is too low so i want to
increase it.
I have another 2 internal time servers (A, B) which must be
synchronized to my MASTER server.
Clients will use A and B servers.

Which time do you suggest me for A, B and MASTER servers ? I know that
these values represent degree of 2.
Maxpoll ?
Minpoll ?
Are These option supported in ntp 4.x in Fedora Linux ?

In article <1173904589.823036.139010@e1g2000hsg.googlegroups.com>,
 "RICCARDO" <castellani.riccardo@tiscali.it> writes:
>I'm going to set Minpoll and Maxpoll time in my ntpd.conf for my NTP
>internal server (MASTER) which must be synchronized to external
>servers (stratum 1 or 2), because I think 64s is too low so i want to
>increase it.

How long did you let your system run?

NTP adjusts the polling interval.  Usually it does the right thing.
If the temperature and/or load on your system and/or the delays on
your network connection are all stable, it should go up to 1024 seconds.
It takes a while.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.

My system is always run (server Master, server A , server B).
I think ntpd polling time was 64s as default but you'are telling me
that ntpd uses variable polling time according to environment and
system status ?
Hal Murray ha scritto:

> In article <1173904589.823036.139010@e1g2000hsg.googlegroups.com>,
>  "RICCARDO" <castellani.riccardo@tiscali.it> writes:
> >I'm going to set Minpoll and Maxpoll time in my ntpd.conf for my NTP
> >internal server (MASTER) which must be synchronized to external
> >servers (stratum 1 or 2), because I think 64s is too low so i want to
> >increase it.
>
> How long did you let your system run?
>
> NTP adjusts the polling interval.  Usually it does the right thing.
> If the temperature and/or load on your system and/or the delays on
> your network connection are all stable, it should go up to 1024 seconds.
> It takes a while.
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.

Riccardo,

Yes, that's right. NTP uses adaptive algorithms to modify the polling
interval.
Usually it starts at 64s and then, at a rate depending on lots of
factors,
increases to 1024s (steady-state).

For details, see slides 4 and 13 of
http://www.eecis.udel.edu/~mills/database/brief/clock/clock.ppt
and also slide 35 of
http://www.eecis.udel.edu/~mills/database/brief/flow/flow.ppt

There's a lot of science in NTP and I would discourage you from
modifying
minpoll/maxpoll unless you have plenty of experience with NTP and
a very good reason for doing it.

Paul

On 15 Mrz., 08:35, "RICCARDO" <castellani.ricca...@tiscali.it> wrote:
> My system is always run (server Master, server A , server B).
> I think ntpd polling time was 64s as default but you'are telling me
> that ntpd uses variable polling time according to environment and
> system status ?
> Hal Murray ha scritto:

RICCARDO wrote:
> I'm going to set Minpoll and Maxpoll time in my ntpd.conf for my NTP
> internal server (MASTER) which must be synchronized to external
> servers (stratum 1 or 2), because I think 64s is too low so i want to
> increase it.
> I have another 2 internal time servers (A, B) which must be
> synchronized to my MASTER server.
> Clients will use A and B servers.
> 
> Which time do you suggest me for A, B and MASTER servers ? I know that
> these values represent degree of 2.
> Maxpoll ?
> Minpoll ?
> Are These option supported in ntp 4.x in Fedora Linux ?
> 

It is generally a BAD IDEA to change the default values of MINPOLL and 
MAXPOLL.  NTPD will change the polling interval to the value within 
those limits that is best suited to the existing situation.  When ntpd 
is first started all the servers will be polled at intervals of MINPOLL 
seconds.  As ntpd gains confidence that it knows what time it is and 
which are the best servers, it will increase that polling interval.  If 
conditions (primarily network delay times) change, it will adjust the 
polling interval for best performance.

Richard B. gilbert wrote:
> RICCARDO wrote:
>> I'm going to set Minpoll and Maxpoll time in my ntpd.conf for my NTP
>> internal server (MASTER) which must be synchronized to external
>> servers (stratum 1 or 2), because I think 64s is too low so i want to
>> increase it.
>> I have another 2 internal time servers (A, B) which must be
>> synchronized to my MASTER server.
>> Clients will use A and B servers.
>>
>> Which time do you suggest me for A, B and MASTER servers ? I know that
>> these values represent degree of 2.
>> Maxpoll ?
>> Minpoll ?
>> Are These option supported in ntp 4.x in Fedora Linux ?
>>
> 
> It is generally a BAD IDEA to change the default values of MINPOLL and 
> MAXPOLL.  NTPD will change the polling interval to the value within 
> those limits that is best suited to the existing situation.  When ntpd 
> is first started all the servers will be polled at intervals of MINPOLL 
> seconds.  As ntpd gains confidence that it knows what time it is and 
> which are the best servers, it will increase that polling interval.  If 
> conditions (primarily network delay times) change, it will adjust the 
> polling interval for best performance.

I'd also like to point out that the increase in the polling interval is
part of the engineering of the algorithms since it also acts as a
dampener to wild swings that may occur as it tries to approach *best
chime*. If you don't understand the algorithms you shouldn't touch the
poll settings.

Danny
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