Ryan Malayter a écrit : > On 5/17/07, Alica CCS <[EMAIL PROTECTED]> wrote: >> All these global pool take over half of traffic. And you know the current >> global pool is not geographically optimized. People querying the global >> pool may get a distant server and inaccurate time (maybe error of a sec?) >> Shouldn't the project do something to correct this? Like IP-based zone >> view for different countries. (the Akamai way) > > This has been tested on a small scale for the pool. The problem is you > are trading widely distributed network resources for a high CPU and > bandwidth load on the DNS servers.
With DNS caching and long TTLs, responses for a whole ISP will be cached on their DNS server for days, so hopefully this should not be too hard on our DNS servers. My earlier testings were small scale (about 150 clients), the next step would be to set up 2-3 servers and a more publicized address (i.e. beta.pool.ntp.org). > There is also the issue of geographically distributing the database > containing pool members and monitoring to make sure they are available > and accurate. Multi-master replication in databases is non-trivial to > set up and maintain. I already have a cron job that does that. Every hour, it logs into www.pool.ntp.org and downloads the global list, parses it and creates a small (63 KB) CDB file that contains the good ntp servers with their geographical coordinates. For fun, it also generates a JPG earth map of the servers: http://guillaume.filion.org/earth_small_ntp.jpg The map also shows the limitations of the GeoIP algorithm: there are about 10 servers in New-Zealand and they all show up at the same spot. That represents the same quality as using nz.pool.ntp.org, which is not too bad. > Akamai can afford this, but can a volunteer project do the same? Hopefully yes! :-) Cheers, GFK's -- Guillaume Filion PGP Key and more: http://guillaume.filion.org/
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