Cost isn’t simple, it varies with a number of factors, including risk.

You’re talking about never having had a failure, which is fine, and, if you’re considering a single node then banking on it can totally make sense. I’m considering 100K+ servers, 1K+ applications and 1K+ databases deployed across 1K+ physical locations. With a mean-time to failure of various components in the 10 years range, that means I need to think in terms of continuous partial failure as the norm. Servers will fail every day, probably in cascades/clusters because that’s how **** happens.

You’re talking about being able to flip things over manually. I’m in a world where a critical failure at the wrong time can cost tens of thousands of dollars per second. How many seconds will it take you to solve the problem? I’m in a world where an increase in latency can cost millions of dollars as people abandon an app, or a site, or a shopping cart in a store.

Say I’m in a highly seasonal business, where our hardware utilization is high for a small part of the year and very low for the rest: *aaS services let me scale and pay for what I need, when I need it. That makes it cheaper in real terms.

Say I have processes that only run 5 * 8. I can turn off my databases for the rest of the week and pay only for storage. That makes them much cheaper.

Combine scaling only when I need it and scheduled shutdowns and I can reduce my costs from *aaS offerings by a really high percentage.

Can you build something that solves those problems yourself? Absolutely! Is it easy or cheap? No, it isn’t. It also isn’t easy to test it and make sure that it will actually work when you need it to. Cloud/*aaS offerings are much more capable of investing the time and energy necessary for that.

Not all money is created equal, either: in general purchasing hardware is a capital expenditure which means I need to carry the value of that hardware for years, pay taxes on the value of it and I need to either have the money or borrow it. SaaS services are all operational expenditure, which makes it more attractive from a taxation and net-present-value of capital perspective.

Say I’m in San Francisco, where the full cost of an employee is somewhere in the region of $250K per year - salary, pension, healthcare, training, insurance, holidays, office-space, travel, etc. etc. etc. If I’m considering 2000 staff, what percentage of our total productive output should we spend on database administration?

Overall, I want to minimize the total cost of ownership of our databases whilst creating an acceptable risk profile and the right performance characteristics. *aaS is sometimes the right option for that, and sometimes it isn’t.

I toss out these figures, not because I, or the company I work for are special, but precisely because we’re absolutely not. There are thousands of companies like us around the world. This is the reality of enterprise software; we’re not optimizing for cost of individual servers, we’re optimizing for organizational level concerns and we’re architecting for risk because - in a big enough corpus of possibilities - ten thousand to one risks happen dozens of times every day.

Your concerns are different from mine, I totally respect that your choices works for you, and I’m not suggesting you should do anything different. It doesn’t work for me and it certainly isn’t always cheaper, in real terms.

The time spent on optimising your postgres config for the hosts they are on, setting up a backup system and regularly testing your recoveries, monitoring the postgres lists for security announcements, etc. To me that is too much hassle to save a few bucks a month. At least until you get up into the $XXXX level on a DBaaS which most people will never hit.

Yeah these are things that aren’t problems until they are and when they are I’m real happy they are someone elses problems. Also if you aren’t spending time optimising your config you’re probably leaving a lot of performance on the table. Which admittedly for most of our projects probably doesn’t matter but it is nice to have it.

The backups gem only does pg_dump style backups so if you have a crash or someone makes a mistake you will almost certainly still lose data. Possibly a lot depending on how often you do snapshots.

I use to run all my stuff on dedicated servers but having each system split off into its own virtual server is just so much nicer for me. I don’t have to worry about a single point of failure, I can easily compartmentalise tools on the server, etc. Now with stuff like PaaS and DBaaS my life is even easier. I’m not paid to be a fulltime admin so the less of it I can do the better.