Source: robertovitillo.com (Check out his book!)
What’s important are not the exact numbers per se but their relative differences in terms of orders of magnitude.
The goal of estimation is not to get a correct answer, but to get one in the right ballpark.
How fast can you read data from the disk? How quickly from the network? You should be familiar with ballpark performance figures of your components.
| Storage | IOPS | MB/s (random) | MB/s (sequential) |
|---|---|---|---|
| Mechanical hard drives | 100 | 10 | 50 |
| SSD | 10000 | 100 | 500 |
| Network | Throughput (Megabits/sec) | Throughput (Megabytes/sec) |
|---|---|---|
| Wired ethernet | 1000 - 10000 | 100 - 1000 |
| Typical home network | 100 | 10 |
| Typical EC2 allowance | 10000 | 1000 |
| AWS inter-AZ | 25000 | 3000 |
| AWS inter-region | 100 | 10 |