Re:Introducing Cloud Spanner, a Global Database Service
by CaveTech on Tuesday February 14, 2017 @03:26PM
(#13646804)
AWS uses heartbeats for detecting liveliness. If x heartbeats fail the failover procedure is started. Generally 10s - 5minutes. In practice (for me) the failover has been less than 15s.
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Re:Introducing Cloud Spanner, a Global Database Service
by macintux on Tuesday February 14, 2017 @03:37PM
(#13646903)
My concern was more around split brain. If you fail over while the write master is simply unreachable, pain results.
Re:Introducing Cloud Spanner, a Global Database Service
by edaemon on Tuesday February 14, 2017 @04:38PM
(#13647449)
Aurora's read replicas share the underlying storage that the primary uses, so AWS claims that there's no data loss on failover. They also claim -- and I've never heard anyone say they were wrong -- that Aurora failovers take less than a minute. So the pain should be limited to under a minute of lost writes, which most applications can handle (with an error). It can still be painful depending on the application.
See here for more info: https://aws.amazon.com/rds/aurora/faqs/#high-availability-an...