On 13.05.2016 15:58, Tom Hughes wrote:
On 13/05/16 14:43, Maarten Deen wrote:
On 2016-05-13 14:59, Grant Slater wrote:
Kudos for the very clear explanation.
Over today (for at least the weekend) we are switching to the new
frontend & backend servers in York (Bytemark). London Imperial will be
offline from approximately 5pm (GMT+1) for the first weekend of power
maintenance.
Is my understanding correct that this will put all servers in York and
eliminate the latency and therefore the slowness?
As of now everything is running in York so that we are ready for the
power to go off in London over the weekend.
On Monday we plan to move service back to London though I will
probably try and keep the uploads going through the backend servers at
York to see if that improves the speed issues seen this week.
In due course the new database server in London will likely become the
master with the one in York as a slave for servicing reads but with
the ability to flip the master over if we need to run from York for
some reason.
Am I also correct to assume that the current situation is only because
of this move (and prompted by the maintenance at Imperial) and is not
planned to be a permanent setup?
Well long term we want to have things spread over multiple sites so
that we can cope with a data centre going down and part of this is us
learning the best way to split things up and arrange things so that we
can achieve redundancy without impacting other things.
So there will likely be some tinkering and experimentation over the
coming weeks as we try different things to see what works best.
Tom
It has got a name: business continuity [1] and disaster recovery [2]. I
read a company in Louisiana could survive a hurricane Katrina because it
moved a mirror server to the city of Houston, in another state, Texas,
just days before the disaster. They had enough of items to ship
physically from the warehouse in Louisiana, and the order processing
system continued to work from Texas without interruption.
[1] https://en.wikipedia.org/wiki/Business_continuity
[2] https://en.wikipedia.org/wiki/Disaster_recovery
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