HIDDEN - Reporting, Backup with out affecting the actual dataset
Arbiter - low resource, voting member
// Highest priority always wins conf = { _id: "mySet", members: [ {_id: 0, host: "A", priority: 3, tags: {"datacenter": "NY"}}, {_id: 1, host: "B", priority: 2}, {_id: 2, host: "C"} // Defaults to priority 1 {_id: 3, host: "D", hidden: true} // Analytics node {_id: 4, host: "E", hidden: true, slaveDelay: 3600} // Backup node. One hour delay. THIS IS AWESOME ] }
- Consistency - RW to primary
- Delayed Consistency - W to primary, R from secondary
** Write Concern **
- Network acknowledment
- Wait for error
- Wait for journal sync - Wait till it is written to disk
- Wait for replication
** Read Preference **
- primary - immediate
- primaryPreferred
- secondary
- secondaryPreferred
- Nearest - nearest in ping (latency)