[barry-cotter]

> I'm not sure that 55 months of up-time indicates it's more or less likely to go down in the next month, but I'd guess more likely.

Less likely

https://en.wikipedia.org/wiki/Lindy_Effect

> The Lindy effect is a theory that the future life expectancy of some non-perishable things like a technology or an idea is proportional to their current age, so that every additional period of survival implies a longer remaining life expectancy. Where the Lindy effect applies, mortality rate decreases with time. In contrast, living creatures and mechanical things follow a bathtub curve where, after "childhood", the mortality rate increases with time. Because life expectancy is probabilistically derived, a thing may become extinct before its "expected" survival. In other words, one needs to gauge both the age and "health" of the thing to determine continued survival.

[viraptor]

It's going to be some mix of Lindy and bathtub. Lindy for the software itself and electronics, bathtub for fans, spinning disks, cables, other things that may physically degrade.

Also, unless the server is in a data centre with some serious redundancies, (and even then...) the power is guaranteed to go down one day.

[RandomBacon]

OP is talking about a phyaical server. The Lindy Effect is for "some non-perishable things". A server that already has already been running for at least 55 monthes is definitely perishable.

[matthewowen]

A server running software has both perishable and non-perishable elements. The physical hardware is perishable and weakens with age, but as the software itself ages the likelihood that it contains bugs like "it crashes whenever daylight savings occurs" decreases.

The question is which effect dominates at a particular point in time.

[cf141q5325]

Its hardware, so you are looking at the bathtub curve https://en.wikipedia.org/wiki/Bathtub_curve

[clarry]

Ideas and technologies are actively sustained by external forces due to perceived merit in said ideas or technologies.

A computer program that is freewheeling along, by contrast, is not sustained by but dependent on external factors (software, hardware, electricity), all of which are prone to fail and some of which are more likely to fail with age.