Load math at 2M per day
2M orders/day: rates you can feel, then the disk horizon
teaching numbers: 2M rows/day, 23.1/s avg, 231.5/s peak, 3 notifications per order
rates per second (bars illustrative, values labelled)
avg orders 23.1/s
peak orders 231.5/s (10x)
avg notifications 69.4/s
peak notifications 694.4/s
payload approx 1 KB: peak approx 0.7 MB/s, one queue is enough
one box, years of headroom
2M rows/day x 1 KB = 2 GB/day
0.75 TB/year incl. indexes (teaching)
4 TB disk holds approx 5.4 years
peak 231.5/s vs 5k/s tripwire: 20x headroom
writes 20x below tripwire: stay single
disk horizon: one 4 TB box at 0.75 TB/year (teaching)
yr1
yr2
yr3
yr4
yr5
1 yr
2 yr
3 yr
4 yr
5 yr
full 5.4 yr
4 TB / 0.75 TB per year = 5.4 years: the disk-horizon tripwire, decided in step 2
legend: blue = order rates, green = notification fan-out, peach = headroom, yellow = disk horizon