[erlang-questions] Maximum number of children for simple_one_for_one supervisor?

[Jay Nelson]

The bigger question beyond launching 1M procs is what happens if
you kill one and try to replace it. I have heard anecdotal evidence
that 100K children is a problem and a tiered supervisor hierarchy
is needed to be able to access/replace children in a performant way
but I am not certain what strategy was being used in the tales.

Supervisor uses sets, dict and list for children, depending on type.

What are you hoping supervisor will do for these children during
the operation of a system? Do you do code upgrade, or automated
process replacement/migration?

The memory and performance requirements are likely wholly
independent of the supervisor (other than yet another copy of
memory being kept by the supervisor to refer to its children). If
you just need to clean them up, a simple link can suffice, but
if they have OTP dependencies the supervisor may offer some
advantages.

jay