Comment by makeitdouble | Hacker News Reader

Comment by makeitdouble | Hacker News Reader

Parent Full thread

I see the parallel you're drawing but even the core idea is I think different enough to be worse dissecting.

In manufacturing, you keep spare capacity to allow for more lucrative orders to come in. If you don't expect any, you run at 100%. For instance when Apple pays TSMC all the money in the world to produce the next iPhone chip, they won't be running that line at 70%, the full capacity is reserved.

Or if you're a bakery, you won't keep two or three cake cooking spots just on case someone comes in witb an extraordinary order, you won't make enough on that to cover the lost opportunity.

We run our servers at 70% or even 50% capacity because we don't have control on what that capacity will be used for, as external events happen all the time. A manufacturers receiving a spike of extra orders can just refuse them and go on with their day. Our servers getting hit with 10x the demand requires efforts and measures to protect the servers and current traffic.

Factories want to optimize for efficiency, server farms want to pay for more reactivity, that's the nature of the business.

I think even for a company like TSMC these ideas are important to understand.

To give you an example TSMC might have a factory with 10 expensive EUV lithography tools, each capable of processing 100 wafers per hour. Then they have 4 ovens, each able to bake batches of 500 wafers per hour.

TSMC could improve efficiency by reducing the number of ovens, because they are running only at 50% capacity. But compared to the cost of the EUV tools, the ovens are very cheap. They need to be able to produce at full capacity, even when some ovens breakdown, because stopping the EUV tools because you don't have enough ovens would be much more expensive then operating with spare capacity.

> Or if you're a bakery, you won't keep two or three cake cooking spots just on case someone comes in witb an extraordinary order, you won't make enough on that to cover the lost opportunity.

I think it's always worth thinking about what you can leave slack / idle space in. For example, you might not keep multiple stations free, but you might invest in a larger oven than you need to make the cakes you currently make. Or you might invest in more bakery space than you need, including extra workspace than you can utilize at 100%. Not because you necessarily anticipate higher demand, but because you might get a customer that's asking for a cake bigger than your standard. Or because you might have a customer placing a large order and need some extra room to spread out more, or to have a temporary helper be able to do some small part of the job even if they can't use the space as a full station.

But also idleness might look like "you don't spend all of your time baking orders for customers". If you never build in slack for creating, experimenting and learning, you'll fall behind your competition, or stagnate if your design and art is a selling point.

Even for a server farm, you can prioritize the web traffic and still use the excess capacity for CI or whatever.

Reply on news.ycombinator.com