So.. interesting topic. Last year I experimented with some C# + Samsung 970 Evo Plus Nvme + MessagePack (with compression) + Zfs .. to benchmark how fast I could dump objects from .net memory to disk.
The numbers involved was insane and I played with various scenarios, with/without compression (MessagePack feature), with/without typeless serializer (MessagePack feature), with/without async and then the difference between using sync vs async and forcing disk flushes. I also weighed the difference between writing 1 fat file (append only) or millions of small files. I also checked the difference between using .net streams versus using File.WriteAllBytes (C# feature, an all-in-memory operation, good for small writes, bad for bigger files or async serialization + writing). I also played with the amount of objects involved (100K, 1M, 10M, 50M).
I cannot remember all the numbers involved, but I still have the code for all of it somewhere, so maybe I can write a blogpost about it. But I do remember being utttterly stunned about how fast it actually was to freeze my application state to disk and to thaw it again (the class name was Freezer :p).
The whole reason was, I started using Zfs and read up a bit about how it works. I also have some idea about how ssd's work. I also have some idea how serialization works and writing to disk works (streams etc).. I also have a rough idea how mysql, postgres, sql server save their datafiles to disk and what kind of compromises they make. So one day I was just sitting being frustrated with my data access layers and it dawned on me to try and build my own storage engine for fun, so I started by generating millions of objects that sits in memory, which I then serialized with MessagePack using a Parallel.Foreach (C# feature) to a samsung 970 evo plus to see how fast it would be. It blew my mind and I still don't trust that code enough to use it in production but it does work. Another reason why I tried it out, was because at work we have some postgres tables with 60m+ rows that are getting slow and I'm convinced we have a bad data model + too many indexes and that 60m rows are not too much (since then we've partitioned the hell out of it in multiple ways but that is a nightmare on its own since I still think we sliced the data the wrong way, according to my intuition and where the data has natural boundaries, time will tell who was right).
So I do believe there is a space in the industry where SSD's, paired with certain file systems, using certain file sizes and chunking, will completely leave sql databases in the dust, purely by the mechanism on how each of those things work together. I haven't put my code out in public yet and only told one other dev about it, mostly because it is basically sacrilege to go against the grain in our community and to say "I'm going to write my own database engine" sounds nuts even to me.