6 ms·

Any chance you could be more specific as to what you feel is missing in the book? Granted, "distributed systems" is a enormous topic that no book can cover ful

• chubot 13y ago
  I'm not sure exactly what the grandparent comment meant, but I think I have an idea. I only skimmed the contents so take this with a grain of salt. Your book is focusing on a pretty narrow part of distributed computing. I would rename it "Managing State in Distributed Systems", or "Distributed Storage Systems". Your examples are Bigtable and Dynamo, which fall in this category. The book seems to be aimed at sort of a "beginning" audience. But the topics are inappropriate for a beginning audience, and skewed for an expert audience. Real distributed systems try to be stateless wherever possible. You need "big computer science" to manage state in distributed systems, but most code in a distributed system should not manage state. These techniques should be confined to specialized storage systems. Here are some examples of real world distributed systems that don't use the described techniques to manage state: - clusters of stateless web servers + single master database (99%+ of websites people use) - message queue / work queue. A single machine can productively manage 1,000 - 10,000 stateless workers, depending on the workload. - MapReduce - Original GFS - Napster - BitTorrent (tracker and trackerless would be interesting to write about) - BitCoin The title seems to imply a practical bent, but it seems more like a collection of ideas (which are important and interesting, but not really what engineers need to know. IMO the #1 skill for distributed computing is to be competent at BOTH programming a single computer and at system administration). If I wanted to be harsh, I would say it looks like you read a bunch of stuff and didn't work with it or implement it? At the very least, the ideas don't seem to be put in the context of commonly deployed distributed systems. People need to understand these simpler, more robust, and more performant techniques, and how to apply them to their specific problem domain, rather than blindly throwing consensus at every problem (which is a disturbing trend I've seen).
  • throwawaykf03 13y ago
    It goes even beyond that. A lot of other very important, fundamental topics belong under the umbrella of distributed systems, starting with routing. The Internet is, after all, a giant distributed routing system. Another topic that's huge all by itself is peer-to-peer networks, and all their associated aspects, such as structured (DHTs like Chord, Cassandra, etc.) vs unstructured (Gnutella, Kazaa, etc.), P2P search, handling churn, handling peers with heterogenous capabilities, peer selection, topology organization, decentralized routing, file-sharing (torrents) vs streaming (PPLive, Spotify), etc. Other topics (with several overlapping aspects) include: - Security, such as Sybil attacks, group key management, etc; - Overlay networks; - CDNs; - Ad hoc and mesh networks; - MMOs and multiplayer games; - SCADA and industrial control systems; - Pub/Sub systems and application layer multicast; - Distributed file systems; - Load balancing and bandwidth management; And that's just off the top of my head... I'm sure I'm missing other important topics.
    • strlen 13y ago
      > It goes even beyond that. A lot of other very important, fundamental topics belong under the umbrella of distributed systems, starting with routing. The Internet is, after all, a giant distributed routing system. Yes! DNS is also fascinating as far as distributed databases and consistency go: http://pages.cs.wisc.edu/~akella/CS740/S08/740-Papers/MD88.pdf‎ http://pages.cs.wisc.edu/~akella/CS740/S08/740-Papers/MD88.p...
    • mixu 13y ago
      Indeed, but ultimately covering all of those topics would require an incredible amount of time and effort. So I need to pick and choose my battles as some topics are more important or interesting to me than others. :)
      • throwawaykf03 13y ago
        Completely understand. But as chubot suggests, the topic of "Distributed Systems" is really broad and something narrower in the title, such as "Distributed Data Systems" may be more apt.
• strlen 13y ago
  Couple of suggestions: 1) I'd avoid mentioning CAP and FLP impossibility result much further in, this is like starting a discussion of mathematical logic or Computer Science with Godel's Incompleteness Theorem. I'd definitely cover vector clocks and causality before: you really need this background in order to understand CAP/FLP. You may want to take a look at the approach Vijay Garg takes in his book: http://www.amazon.com/Elements-Distributed-Computing-Vijay-Garg/dp/0471036005/ref=sr_1_4 http://www.amazon.com/Elements-Distributed-Computing-Vijay-G... (E.g., use of vector clocks for proofs) 2) Don't over-focus on "webscale" (using the term only semi-ironically here) projects (I say this having contributed to multiple such projects). NFS, AFS, and CodaFS all raised very interesting questions about distributed state and disconnected operations. You may also note how some of the authors on the Plan9 (9fs, 9p, fossil) papers overlap with authors of some of the Google papers. "Mobile sensor networks" have been essentially an excuse to build distributed systems. Chord, Pastry, and Kademelia (sp? The System that Bittorrent uses) -- are actually far more truly "distributed" than many webscale systems (consistent hashing is a very simple DHT). Finally, don't forget that the Internet itself is a distributed system: the most successful eventually consistent, highly available distributed database is DNS. I'd actually cover the web-giant infrastructure paper stuff a bit later on. While the Dynamo paper did have some novel contributions (regarding Gossip and anti-entropy), it's not what it's notable for: what's far more interesting in that paper is the way these concepts fit together. I'd even hold my nose and cover CORBA: it's an interesting example in that it handled everything by the textbook, but failed due to complexity costs it had to incur in order do that. Far simpler RPC protocols and Web Services prevailed at the end by promising less. JINI may also be interesting to cover -- excellent system, far too ahead of its time -- Java VM and ecosystem were immature (anyone else remember Blackdown JDK on Linux?), marketed incorrectly (driver architecture?) to a market that wasn't ready for it (this is when dot-com startups could suffice on buying a couple of E10Ks or high-end Alphas). 3) This is an enormous and highly ambitious project and I commend you from embarking on it (I just re-read http://paulgraham.com/hs.html http://paulgraham.com/hs.html -- see the part about hard problems and ambition). Nonetheless, if you're serious about this, be sure to get plenty of editors -- there's a lot of room to make subtle mistakes (which I've done all the time). A lot of this can be genuinely confusing -- e.g., partitions aren't just due to networks, but at the same time not every type of a failure or a stop is a partition (I used to site GC pauses an example of a partition, but now I'm not so sure). I'd help, but I've neither the cycles nor the habit of academic rigor; if you're still in touch with any profs from your uni, they could either help themselves or point you to others.