The maths most SAN engineers do not understand in context of Database Servers 6

I suppose I write this post to mock some of the things I keep seeing in the industry today. Directly Attached Storage (DAS) has moved on dramatically in the past 5 years, a single SSD has the capability of up to 525MBytes/sec throughput (SATA/SAS 6Gbits/sec), 700MBytes/sec (M.2) and then there is PCIe connected flash operating at multiple GBytes per second.

I will simply put a picture, if you understand what I’m portraying then you are like the rest of us – understand maths and common sense.

A clue: what happens when you drive down a 10 lane motorway that get’s reduced to just a single lane?

In the diagram below the database servers have a reporting role so pull much data from storage.

What is wrong with the architecture below? Assume data is located on a single LUN across all the SSD’s.

SAN Bandwidth