| It is a useful paper, yes. Good examples, good diagnosis of issues in systems theory, good definition of a way forward. However it suffers from (a) weak definitions and (b) implausible or strange descriptions. For (a), what is a "strong feedback loop"? Does it have high gain (low error) or high bandwidth (fast)? Is it hidden (the accidental link imbalance example)? Is it obvious (the cold cache example)? What makes it "strong"? Or, conversely, what is a "weak" feedback loop? A number of acronyms are undefined (SRE, LIFO). I think I know what they mean, and most HN readers will too. What about the other readers? And using Wikipedia to define metastability? There must be a more persistent or academically defendable reference. Wikipedia is OK for informal definitions. In a paper calling for more academic studies this is ironic. (b) Section 2.1 "When replicas are sharded differently..." Huh? Section 4 "upper bound" used as a verb. Should be "limit or place bounds on". Section 4 "The strength of the loop depends on a host of constant factors from the environment..." Odd, the term is not defined but this is the second dependency listed. Very strange. In short it needs/needed a better reviewer. That all said, it has summarized a lot of good ideas on controlling stability in distributed systems. Other references may be found in Adrian Colyer's "the morning paper". No longer updated but has many years of good references. See blog.acolyer.org. |