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Comment by tenaciousDaniel | Hacker News Reader

I'm considering moving from a self-hosted Mongo setup to Aurora, either with PG or MySQL. Anyone here have opinions on Aurora?

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It does the job, but aurora postgres lags behind mysql when it comes to features. Failovers are surprisingly slow, too. You're pretty much stuck with cloudwatch for monitoring, which has significant lag.

> aurora postgres lags behind mysql when it comes to features

And performance, on some workloads we tested. I would benchmark write performance very carefully before using Aurora Postgres (Aurora MySQL does not seem to suffer from the same issue on the same workload).

> Failovers are surprisingly slow, too.

The recommendation now is to use RDS Proxy for faster failovers.

Aurora (Postgres) looked like it would be great, and the performance for our use case was much better than RDS. But there was a showstopper for us with the replication: If the cluster leader fails, _every read replica will force a restart_ to elect a new leader, resulting in minimum ~30s complete cluster downtime. In our situation we have no problem with a short downtime in write availability, but the fact that we can't maintain read availability via replicas is a deal breaker.

I'm no DBA, but is that not the entire point of a cluster/replicas?

Sure, maybe writes won't be accepted or replicated until a new master is elected, but you can't even read from the cluster?

I'm curious at this point: what is it exactly that you gain from a cluster? Is it only having to wait 30s vs. however long it takes for the master to come back online?

That was the mind-boggling part to me. After testing failover and noticing the behavior we had a number of discussions with AWS reps and support engineers that confirmed it. And Aurora's failover documentation hints at it but downplays the severity.

The thing you gain from the replicas is removing read load from the primary during normal operations.

If you're thinking of going for the version that auto sleeps when not in use be aware there's a 30-40 second startup time from first incoming request. If it's a database you don't need to be accessible except in bursts this can be really handy for cutting costs as you're not paying for any read/write resources you're not using. Of course if you do need it generally accessible all the time then you'd want to provision it accordingly.

I've heard mixed reviews on Aurora MySQL. Some people move to it and see huge performance gains, others simply don't or have some limitations.

Do you have some examples of limitations they faced?

Honestly I don't sorry.

I would suggest checking out other smaller cloud providers for managed databases over Aurora. Check out Aiven.io

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