On 2023-04-11 17:19, Jim Pennino wrote:
Renzo Marengo <buckroger2...@gmail.com> wrote:
In my wide area company with about 1000 clients, I organized ntp server
hierarchy in 2 levels:
level A - n.1 Physical Linux server (Centos 6) - SERVER MASTER
level B - n.3 Physical Linux server (Centos 6) - NTP1, NTP2, NTP3 (for clients)
Server MASTER retrieves time directly from servers of public newtwork.
Server NTP1, NTP2, NTP3 retrieves time from server MASTER and they are the
official NTP server used from clients.
What do you think about this ntp server structure? I know NTP server numbers
must be 1, 3 or 4,....
I know ntp server must be a physical machine because its clock is more exact.
Right ?
Each ntp server or client that uses other ntp servers to get time needs
at least 3 servers so it can tell if one of the servers goes wonky. If
you want redundancy you should have 4.
I wonder when and why this advice changed from 3 to 4. When I started
setting up local NTP networks more than 15 years ago, the documentation
advised setting up 3 local servers sourcing from 3 online servers each
(when not having access to non-ntp sources such as NIST dial in, long
wave time signals, GPS, Caesium/Hydrogen frequency references etc.
This was before good pool sources, so I had to work through the list of
public servers on the project webpage and choose some that would be
polite to use as master references while constraining internal machines
to contact only the internal NTP servers.
The stratum of servers in general makes no significant difference unless
you are doing something special, like timing nuclear reactions.
The simplest thing to do is use at least 3 ntp appliance boxes, each of
which will be at stratum 1, for the entire company network.
You can find GNSS based ntp appliance boxes on ebay and other places for
about US$80 these days that consist of an active antenna, a small box
roughly the size of a pack of cigarettes and a 12V power adapter.
Search for ntp time server on ebay for examples.
The advantage to using an appliance is that there are no computers to
obtain, configure, maintain, or find a place for and they only use about
1W of power each.
All you need to do is put the antenna on a window sill, connect the
antenna, power and network and set the IP address you want for the box.
If your company has multiple locations, spread the boxes across
different locations so there is no single point of failure.
Then point all 1000 clients to your boxes.
Enjoy
Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded
--
This is questions@lists.ntp.org
Subscribe: questions+subscr...@lists.ntp.org
Unsubscribe: questions+unsubscr...@lists.ntp.org
