[time-nuts] Noob question, NTP stratum 1.

[K5ROE Mike]

You may want to look at something an Endrun CDMA ntpserver for the 
datacenter; don't need view of the sky. Available on the used market sub $1k

Standard solution for this scenario.


K5ROE Mike

On 7/22/19 10:50 AM, wildylion via time-nuts wrote:
> Yeah, of course I will NOT do anything home-grown for the datacenter.
>
> But currently it uses 3 Stratum 2 NTP servers, one per DC, with them referencing a list of 4 close-by Stratum 1 sources.
>
> ntpstat generally says that time is correct within ~50 ms, while jitter and offset generally don't exceed 1ms, the root dispersion is quite large.
> Also these Stratum 2 NTPs are run from Cisco routers, which I doubt are very good at timekeeping.
>
> When I implemented this scheme, I offered to have S2 on a set of x86 servers, but was overruled by management who said it'll be better if we run S2's off Cisco gear.
>
> So what if we add a couple GPSDO's into the mix, using them as primary time sources alongside public Stratum1 NTP servers for sanity check? And of course moving the S2's to something more stable.
>
> My own, homegrown S1 pool NTP is another matter entirely - I think just a tuned Raspi with a M8N will be enough?
>
> Sent with [ProtonMail](https://protonmail.com) Secure Email.
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Monday, 22 July 2019 г., 17:38, Taka Kamiya <tkamiya9 at yahoo.com> wrote:
>
>> If you have 100 production servers with database, I am going to strongly discourage you from taking a "home grown" route.  You will need multiple redundant implementation with fail-over.  You mentioned budget.  How much are your bosses willing to pay for consultation fees for failed or corrupted data?  I am assuming you are talking about Oracle RDBMS with minimum of 2 way RAC.
>>
>> If you are using collocation services, doesn't the center itself offer ntp service for fee?
>>
>> If you need 24 hour hold-over, I will take nothing less than multiple ovenized crystal OSC GPSDO with redundancy per center.  Then feed that into ntp server with multi-location fail over.
>>
>> If I were responsible for managing such system and if my boss will want me to go cheap route, I will seriously fight it.  If it's successful, your boss will get credit for spending little and getting a big benefit.  WHEN it fails, it's going to be your fault for not mitigating risk sufficiently.  Try pricing out 2 days of consulting fees....
>>
>> ---------------------------------------
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
>>
>> On Monday, July 22, 2019, 10:05:56 AM EDT, wildylion via time-nuts <time-nuts at lists.febo.com> wrote:
>>
>> Hello there,
>>
>> I wanted to ask for advice regarding NTP
>>
>> Situation 1:
>> What I currently have is a uBlox M8N GPS puck I'm planning to use with the Raspberry PI. Seems like it should work almost out of the box with some kernel tuning, but I have a question about short term stability in the event of GPS loss - how well will the board hold over if it's lost GPS for, say, 24 hours?
>>
>> Situation 2:
>> Also, there's a need for more dependable NTP time sources for our colocated spaces.
>>
>> What we have is about 100 servers, some of them running DBMS that wouldn't like clock drift at all. After a recent incident involving NTP I've got an idea to install GPSDO time servers in each datacenter and slave them to stratum2's that will be actually distributing time to clients.
>>
>> All the certified GNSS disciplined clocks are really expensive (way more than the management would approve), so what I'm planning to do is possibly getting a couple LeoNTP units and using them as the root time sources, would this be a good plan? Of course, all the NTP infrastructure will be monitored, and possibly we'll use Stratum 2 servers which would be slaved to GPSDO S1's AND the public NTP pool for sanity checks.
>>
>> Maybe BG7TBL's units instead of LeoNTP?
>> Is that a good idea?
>>
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