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Does running on 3-5 machines give you the advantage of being able to apply kernel patches and restart machines without bringing down the whole system? That migh
by oconnor663 8y ago
Does running on 3-5 machines give you the advantage of being able to apply kernel patches and restart machines without bringing down the whole system? That might matter to people with paying customers, even if in theory they could've replaced their 3 machines with one bigger one.
- Quekid5 8y agoIt may, but if your customer can't tolerate/afford 5-10 minutes of downtime you're already into "big league" territory. I could see a case if you're rolling out gradually, but with only 3-5 machines you're not really going to notice any subtle problems in a 1-vs-2 or 2-vs-3 situation.
- mmt 8y agoI'm not sure anyone would ever actually have only one machine, without a failover option, and failing over had better not bring down the whole system.
- yjftsjthsd-h 8y agoBut now we're back to a distributed system
- mmt 8y agoI don't think that's true, in the usual sense of the term. When a replica is used as a read slave, that introduces problems with (strong) consistency, that definitely starts to resemble any other distributed system. Adding automated failover adds the need for some kind of consensus algorithm, another feature of distributed systems. However, if failover is manual, for example, then 2 nodes can be nearly indistinguishable from 1 node, if no failover occurs. It also strains the definition of "distributed" if both nodes are adjacent, possibly even with direct network and/or storage connections to each other.