May also want to add that seed nodes do not auto bootstrap. Thanks Aaron On 22 Apr 2011, at 13:24, Maki Watanabe wrote:
> Thank you, Naren. > I'll add some more details and upload it to FAQ wiki page. > > maki > > 2011/4/21 Narendra Sharma <narendra.sha...@gmail.com>: >> Here are some more details that might help: >> 1. You are right that Seeds are referred on startup to learn about the ring. >> 2. It is a good idea to have more than 1 seed. Seed is not SPoF. Remember >> Gossip also provides eventual consistency. So if seed is missing, the new >> node may not have the correct view of the ring. However, after talking to >> other nodes it will eventually have the uptodate state of the ring. >> 3. In an iteration Gossiper on a node sends gossip message >> - To a known live node (picked randomly) >> - To a known dead node (based on some probability) >> - To a seed node (based on some probability) >> >> Thanks, >> Naren >> On Wed, Apr 20, 2011 at 7:13 PM, Maki Watanabe <watanabe.m...@gmail.com> >> wrote: >>> >>> I made self answered faqs on seed after reading the wiki and code. >>> If I misunderstand something, please point out to me. >>> >>> == What are seeds? == >>> >>> Seeds, or seed nodes are the nodes which new nodes refer to on >>> bootstrap to know ring information. >>> When you add a new node to ring, you need to specify at least one live >>> seed to contact. Once a node join the ring, it learns about the other >>> nodes, so it doesn't need seed on subsequent boot. >>> >>> There is no special configuration for seed node itself. In stable and >>> static ring, you can point non-seed node as seed on bootstrap though >>> it is not recommended. >>> Nodes in the ring tend to send Gossip message to seeds more often by >>> design, so it is probable that seeds have most recent and updated >>> information of the ring. ( Refer to [[ArchitectureGossip]] for more >>> details ) >>> >>> == Does single seed mean single point of failure? == >>> >>> If you are using replicated CF on the ring, only one seed in the ring >>> doesn't mean single point of failure. The ring can operate or boot >>> without the seed. But it is recommended to have multiple seeds in >>> production system to maintain the ring. >>> >>> >>> >>> Thanks >>> -- >>> maki >> >> >> >> -- >> Narendra Sharma >> Solution Architect >> http://www.persistentsys.com >> http://narendrasharma.blogspot.com/ >> >>
