[Osmf-talk] API Failover

Paul Norman penorman at mac.com
Mon Oct 27 21:59:24 UTC 2014

On 10/27/2014 9:21 AM, Joseph Reeves wrote:
> As someone involved in this original twittering, I didn't read the 
> message like that. Sure $150k is a lot of money to keep the DB 
> available during a planned reboot, but it would appear to be a very 
> small amount of money to spend in order to keep the OSM database 
> online if something catastrophic was to happen to the server it 
> currently lives on. This weekend's interruption was brief; there has 
> been larger interruptions in the past and there's always the 
> possibility that Something Bad is going to unexpectedly happen.
There are redundancies in place to cover the case of a server failure of 
one of the database servers. I wasn't involved in the planning of the 
recent database server switchover, but I know it is substantially easier 
to switch master and slave database servers if you can switch to read-only.
> I'm sure that database replication could also lead to some powerful 
> use cases that aren't available to us yet: Performance improvements in 
> places far from London, perhaps.
Having done a GSoC project on software that could be used for 
distributed read-only API mirrors, I'd say the issues holding them back 
are not hardware funding related, but time related. Having also run a 
read-only API mirror, I know first-hand that it's actually a lot less 
effective than you might think, particularly from North America.

No special access to the servers is required to run a read-only API 
mirror - all the data is publicly available.

This is something that would be reasonable for an organization like HOT 
to fund, or if someone wanted OSMF blessing for a grant proposal, I 
would expect the board would indicate approval if it would help get funding.

The technical details aren't really a matter for osmf-talk@, but if 
someone wants to discuss it in more detail, I'm probably the person most 
familiar with it, or the dev@ mailing list is suitable.

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