The section warned in general and so warned about nothing. An operator
reading "it can fail in ways it cannot undo" learns less than one reading
that the window is usually longer than guessed, that opening the source
store with the new server ends the rollback permanently, that a rollback
after mail has flowed does not bring that mail with it, and that a
certificate which stops renewing says nothing for ninety days. Each of
those has been measured or seen; each has something the operator can do
about it.
Also sharpens the part that matters most and is easiest to get wrong: the
old install is a service safety net, not a data one. One copy, same
machine, one moment. A backup is a copy elsewhere that has been restored
from, and anyone who cannot say when they last restored one does not yet
know whether they have one.
And replaces the flat line about nobody else being responsible with what
it was trying to say: the operator carries the outcome, because this is
software running against a server it has never seen, holding data somebody
else depends on.
jcoffey-dev
848bfeda4e