| > Clusters of stateless web servers + single master. This is definitely a common setup, but you need very little if any distributed systems research to implement it. First, define "stateless"? I would not characterized such a system as stateless at all. Even if you're not using sticky sessions (with cache servers/load balancers talking to each other for failover using fairly involved protocols), there's still state that's ephemeral (sessions) in your application server, as well as bulk of the persistent state that's provided with essentially "faith based consistency" (consider typical memcached cluster with client doing consistent hashing -- asynchronously replicated MySQL with failover, etc... -- in case of a failure, neither availability nor consistency are guaranteed). On the level of protocols design, the whole idea of stateless protocols (REST) vs. stateful ones (sticky load balancers + SOAP, CORBA, RMI, etc...) is by itself a big distributed systems topic. A web browser talking to a web server is by definition a distributed system. I am typing this as fast as I can, praying not to get the "your link is invalid" error from HN right now -- this a real example of distributed system and cache coherence/consistency/atomicity. Here's one paper that deals with just these sorts of question (in context of NFS): ftp://ftp.cs.berkeley.edu/ucb/sprite/papers/state.ps > Re: Chubby and GFS Original GFS doesn't rely on Chubby, BigTable does however (for metadata). I believe newer versions (Collosus) by extension rely on Chubby as they rely on BigTable. F1/Spanner, however, use consensus and transactions far more than others and is very interesting in this sense. [Edit: more elaboration on distributed systems issues in a "stateless" cluster of web servers]. |