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Sizing

Introduction

This section contains an estimate of the computational and other resources likely necessary to support expected demand in a country similar to the United States.

Time required to fulfill queries for a single flight

  1. Assume 1 ISA per flight (worst case)
    1. 2 ISA management queries per flight (create & delete)
  2. Assume 90% of flights are nominal and require 3 strategic deconfliction queries (Accepted, Activated, Ended) while 10% of flights have problems and require 7 strategic deconfliction queries
    1. 3.4 strategic deconfliction queries per flight
  3. Assume 0.1 seconds to fulfill a query
    1. Therefore, 0.54 seconds required (on average) to fulfill management queries to support a flight

Time required to fulfill queries for a RID Display Provider

  1. Assume 2 Display Providers viewing each flight on average, 4 subscriptions per flight per DP, and 40% chance of subscription reuse
    1. 9.6 subscription queries per flight
    2. 0.96 seconds required (on average) to fulfill viewing queries to support a flight

Required parallelism

  1. Use 348,537 remote pilots in 2024
  2. Assume 100 flights per month per remote pilot
  3. Use 989,916 recreational pilots as a baseline (even though this is likely number of aircraft, not number of pilots) and double it for the future
  4. Use 7.1 flights per month per recreational pilot
  5. Therefore, expect about 18.6 flights per second
  6. With 1.5 seconds of query time per flight, a nominal parallelism of 28 is required to satisfy the demand
  7. Assuming a peak-average ratio of 3.5, a parallelism of 98 is required

Required resources

  1. With Cockroach Labs guidance of 4 parallel operations per vCPU, the DSS pool requires 25 vCPUs.
  2. Assuming 3 DSS instances and the need to continue to operate when one instance is down, each DSS instance requires 13 vCPUs.
  3. Using 8-vCPU virtual machines (like n2-standard-8), this means each instance needs 2 of these virtual machines
  4. Assuming that 5 days' worth of flights are occupying space on disk at any given time and that each flight record on disk is 100k, approximately 83 GB of storage is required
    1. Note that Cockroach Labs recommends 4,000 read IO/s and 4,000 write IO/s, and some cloud providers scale storage speed with storage size, so 83 GB of storage may be far less than is necessary to achieve these speed numbers