On 2011-12-22, ben slimup <slimu...@hotmail.com> wrote: > > > Hi Terje, > > if i do not use nat how can i route private adresse to internet ?, i do not > want to use ipv6.
You have your ntp servers outside the nat router. He did not say "Never use nat" he said not to use nat for ntp. > > also i m planning to 2 boxes with 3 card on each site, how can i load balance > between site if i m do not use round robin? Single site failure. A failure of any kind on any one of those boxes takes down 3 cards. Why do you have 3 cards on one machine? What is the purpose of that? > > Thank for your support > > >> From: "terje.mathisen at tmsw.no"@ntp.org >> To: questions@lists.ntp.org >> Date: Thu, 22 Dec 2011 12:44:07 +0100 >> Subject: Re: [ntp:questions] ntp server pool advice >> >> ben slimup wrote: >> > >> > Thank for prompt answer Chris, >> > >> > Unfortunately, this ntp network should give time to specific clients >> > devices and not anyone on the public network. >> > >> > according to your advice, better not using load balancer, thats good >> > how to load balance between ntp server if i do not use round robin? >> > if all client choosing the same server then the ntp server will be >> > overload. is it a problem if for example client 1 poll or synch with >> > server 1 , and then with server 2 , etc...? or udp roundtrip comes >> > each time from different ntp server? how many ntp servers should be >> > needed to handle that much request knowing that each card handle >> > 10,000 request per sec? >> >> First, each client should have at least 4 configured servers, so you can >> use the same ntp.conf file for all of them. >> >> Second, if you really can handle 10K requests/second per card, then that >> means that you can handle 640K clients per card, with worst-case polling. >> >> I.e. servers capable of 10K/second should handle your expected load just >> fine, even though a proper (FreeBSD-based) 1U server with a GPS will >> serve even more clients with better time performance. >> >> Terje >> > >> > much appreciate your expertize >> > >> > cheers >> > >> >> From: albertson.ch...@gmail.com Date: Wed, 21 Dec 2011 19:43:53 >> >> -0800 Subject: Re: [ntp:questions] ntp server pool advice To: >> >> slimu...@hotmail.com >> >> >> >> On Wed, Dec 21, 2011 at 5:07 PM, ben slimup<slimu...@hotmail.com> >> >> wrote: >> >>> >> >>> Dear all, >> >>> >> >>> Thank you very much for support, >> >>> >> >>> i do not have 1000,000 client, i need those ntp servers to serve >> >>> a load between 100000 to 1000000 clients over a public network >> >>> with an accuracy of 100ms >> >>> >> >>> those clients will use dns round robin to resolve 4 external ip, >> >>> 2 IPs on each site. i have 4 servers with 4 ntp server slot card >> >>> each ( meinberg M900) 1 ntp server card can support 10,000 >> >>> request. >> >> >> >> First off the good news. 100ms is an "easy" spec to meet you can >> >> do this without a lot of effort. >> >> >> >> Don't let the outside world "see" your meinberg servers. Build >> >> out a layer of "statum 2" servers and expose those to your clients. >> >> 1M clients is a lot for the little 386 class CPU that is in the >> >> meinberg box. >> >> >> >> I still don't understand, Why do all those NTP clients need to go >> >> to your NTP servers. Why can't they use any they like? Are your >> >> servers doing something special? >> >> >> >> Also know that EACH client needs to be configured to see multiple >> >> NTP servers. practically three servers is a minimum but others >> >> will argue for more for five >> >> >> >> A would not use load balancing for NTP servers. With NTP it >> >> does not matter at all if a server crashes. The clients are all >> >> configure to use five servers and if one crashes they will do fine >> >> using four. If you expose four, large robust servers one on each of >> >> your four IP addresses then you will be fine, even if one fails you >> >> will be fine. The clients will notice the failure and continue on >> >> using the remaining three. >> >> >> >> >> >> I technical question for the list: Would Round Robin load >> >> balancing even work. I think it would introduce so much jitter the >> >> server would be usless. I think you have to be sure that each >> >> time a client pools a server at a given IP address it polls the >> >> same physical server. >> >> >> >> Chris Albertson Redondo Beach, California >> >> >> -- >> - <Terje.Mathisen at tmsw.no> >> "almost all programming can be viewed as an exercise in caching" >> >> _______________________________________________ >> questions mailing list >> questions@lists.ntp.org >> http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
