NVME read latency is around 100usec, a SQLite3 database in the low terabytes needs somewhere between 3-5 random IOs per point lookup, so you're talking worst case for an already meaningful amount of data about 0.5ms per cold lookup. Say your app is complex and makes 10 of these per request, 5 ms. That leaves you serving 200 requests/sec before ever needing any kind of cache.

That's 17 million hits per day in about 3.9 MiB/sec sustained disk IO, before factoring in the parallelism that almost any bargain bucket NVME drive already offers (allowing you to at least 4x these numbers). But already you're talking about quadrupling the infrastructure spend before serving a single request, which is the entire point of the article.

▲ f311a 12 hours ago | parent | next [-]

You won't get such numbers on a $5 VPS, the SSDs that are used there are network attached and shared between users.

▲ 100ms 11 hours ago | parent [-]

Not quite $5, but a $6.71 Hetzner VPS

    # ioping -R /dev/sda

    --- /dev/sda (block device 38.1 GiB) ioping statistics ---
    22.7 k requests completed in 2.96 s, 88.8 MiB read, 7.68 k iops, 30.0 MiB/s
    generated 22.7 k requests in 3.00 s, 88.8 MiB, 7.58 k iops, 29.6 MiB/s
    min/avg/max/mdev = 72.2 us / 130.2 us / 2.53 ms / 75.6 us

▲ 100ms 10 hours ago | parent | prev [-]

Rereading this, I have no idea where 3.9 MiB/sec came from, that 200 requests/sec would be closer to 8 MiB/sec