Aurora is very cool but won't help you much after you vertically scale your master and still need more write capacity. With Cloud Spanner you get horizontal write scalability out of the box. Critical difference.
Per their pricing page[1] it looks like the largest instance available is a "db.r3.8xlarge", which is a special naming of the "r3.8xlarge" instance type[2] which is 32 cpus and 244gb of memory.
That's a hell of a lot of capacity to exhaust, especially if you're using read replicas to reduce it to only/mostly write workloads. Obviously it's possible to use more than this, but the "sheer scale" argument is a bit of a flat one.
You can disagree on that if you'd like, but note that I explicitly acknowledged the possibility of exceeding these limits. In my opinion, for most cases/workloads, it's highly unlikely that you will and designing for that from the outset is a waste of time and resources.
Yes, Aurora has a single write master, though it does have automatic write failover -- i.e. if the Aurora primary dies, one of your read replicas is promoted to the primary and reads/writes are directed to the new instance. That does constrain your primary's capabilities to the largest instance size (currently a db.r3.8xlarge).
I don't have a good idea what the upper limit is for an Aurora database setup.
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.
That's vague. AWS also powers huge websites and Amazon is recommending Aurora as the "default choice" for most workloads.[1] There are certainly significant architectural differences but I would say we can definitely make a direct practical comparison.
And their needs are reasonably complex. They use machine learning and big data analytics to generate the list of videos that you should be watching. In order for those to work they need to capture a whole raft of end user metrics e.g. at what point you paused video X.
While Aurora doesn't provide true horizontal scalability, the same-node scalability seems so strong it might allow many companies to stay single-node for quite a while.
It is not close to equivalent. But I do want to get a better feel for if Google really has figured how to do basically the impossible. I want to see if this truly scales horizontally but of it does then competitors better hope for a much more detailed paper :)
It's equivalent, with different (unknown) constraints. Aurora is specifically for scaling workloads in the same way. You can say it's horizontal (machine) over vertical (resource) but it's all a matter of accounting.
The big nono is the Spanner pricepoint. I will stick with Aurora for scaling based on traffic I use, over pricey timeslices.
You would have to have quite a load to justify the switch from cheaper de jour solutions right now (AWS). Relying on the few that do, is a risk.
