3 ms·

Cost is complicated because we autoscale from 2-3 readers up 10+ readers during peak traffic. Instead of running 10 replicas 24/7, we can spin one up and within

Cost is complicated because we autoscale from 2-3 readers up 10+ readers during peak traffic. Instead of running 10 replicas 24/7, we can spin one up and within about 10 minutes it's handling reads. So we have a few instances that only run for about 3 hours a day and others that run maybe 6 hours. That is a big cost savings over running them all 24 hours a day. We couldn't bring up new replicas like that when we were on normal Postgres RDS. Pricing is also surprising compared to vanilla Postgres RDS because reader nodes double as spare writers. A multi-az deployment of Postgres RDS plus two single-az replicas is more expensive than a 3 node (1 writer and two readers) Aurora cluster. E.g. on 2xlarge instances, this Aurora setup is $3.48/hour vs $4/hr on RDS for similar effective hardware and fault tolerance. Running directly on EC2 is going to be much cheaper obviously. $1.51/hr for three 2xlarge instances(if you want to failover to an active replica) or $2.01/hr for 4 if you want a dedicated failover instance (like RDS does).

agacera 7y ago
Aurora is indeed amazing. However, my experience with it regarding costs is that main cost you have running it is not compute, but IO ($0.2 per million requets [1]). This cost is kind of hidden since to estimate this in the early stages of a project is an art. In one project on my team the IO cost is about 8x more than cost of instances. But imo it is still worth and I never actually calculated how much we would pay if we were running on RDS + provisioned IOPS.
- phamilton 7y ago
  It is really hard to estimate because it isn't quite apples to apples. With Aurora we pay for what we use, not what we provision. We used to have some big write spikes for about 5 minutes each hour and so had to massively over-provision IOPS. With Aurora we just pay for the IOPs we use on those spikes. Right now, on a multiple of the traffic we had before we moved to Aurora we are paying less than half what we used to for IO.

agacera 7y ago

Aurora is indeed amazing. However, my experience with it regarding costs is that main cost you have running it is not compute, but IO ($0.2 per million requets [1]). This cost is kind of hidden since to estimate this in the early stages of a project is an art. In one project on my team the IO cost is about 8x more than cost of instances. But imo it is still worth and I never actually calculated how much we would pay if we were running on RDS + provisioned IOPS.

phamilton 7y ago
It is really hard to estimate because it isn't quite apples to apples. With Aurora we pay for what we use, not what we provision. We used to have some big write spikes for about 5 minutes each hour and so had to massively over-provision IOPS. With Aurora we just pay for the IOPs we use on those spikes. Right now, on a multiple of the traffic we had before we moved to Aurora we are paying less than half what we used to for IO.