Mongodb admin notes

mongo_admin.txt

Start mongodb replica servers:

mongod --replSet abc  --dbpath /db/1 --port 27001 --oplogSize 50 --logpath log.1 --logappend --fork --rest
mongod --replSet abc  --dbpath /db/2 --port 27002 --oplogSize 50 --logpath log.2 --logappend --fork --rest
mongod --replSet abc  --dbpath /db/3 --port 27003 --oplogSize 50 --logpath log.3 --logappend --fork --rest

Basic config for a replica set:
cfg=
{
	"_id" : "abc",
	"version" : 1,
	"members" : [
		{
			"_id" : 0,
			"host" : "localhost:27001"
		},
		{
			"_id" : 1,
			"host" : "localhost:27002"
		},
		{
			"_id" : 2,
			"host" : "localhost:27003",
		}
	]
}

rs.initiate(cfg)
[ rs.reconfig(cfg) ]

options: store arbiterOnly / priority / hidden / slaveDelay / (votes)
priority - how likely it will be master (0=never)
slaveDelay - db which is X seconds delayed (requires big oplog, priority always 0)

Run commands on slave:
rs.slaveOk()

Check on things:
>rs.status()