
Finding the closest data center using GeoIP and indexing - alonswartz
http://www.turnkeylinux.org/blog/geoip-amazon-regions
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fragmede
Is the physically closest data center always the closest wrt routing? I'd
think the more important metric is number of hops and ping time over sheer
geographical proximity.

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alonswartz
I totally agree that basing solely off geographic location is not adequate, so
let me clarify the implementation details.

In production, we use GeoIP to determine the country/state of the server in
question, and then perform a lookup in the generated indexes to determine the
preferred region. I say preferred (and not closest) because the indexes are
static, and are not calculated on the fly. This was a design decision to allow
us to tweak the indexes with the help of community feedback.

The location based calculation described was used to generate the baseline
indexes to provide a relatively good starting point. One of the reasons for
writing this blog post and publishing the indexes, was to take us to the next
phase of tweaking the indexes, hence the closing paragraph:

"we need your help to tweak the indexes - as you have better knowledge and
experience on your connection latency and speed. Please let us know if you
think we should associate your country/state to a different Amazon region."

The countries and US indexes consist of 249 and 62 entries, respectively. We
don't have the resources to perform latency testing in each and every
location, for that we need the communities help.

