PostgreSQL 12 High Availability Cookbook - Third Edition

A networking example

This may be easier to visualize with a real example. Let's start with a very active database that has one streaming replica, and one off-site archive. Furthermore, connected clients regularly fetch five million rows per second. Let's work through our steps:

1. 2 * 160 = 320 MB/s
2. 5,000,000 / 10,000 = 50 MB/s
3. 320 + 50 = 370 MB/s
4. 370 * 2 = 740 MB/s

That's a very high value! A 1 Gb/s interface can only supply 100 MB/s at most, so we would need eight of those to produce the necessary bandwidth. Yet a 10 Gb/s interface can supply 1,000 MB/s, so it can easily handle 740 MB/s and have room to spare. Would we rather have eight network cables coming out of our server, or one?