00466802 - Split Replica Set

killall mongod
rm -rf repl3
mkdir repl3
mlaunch init --replicaset --nodes 3 --dir repl3 --hostname localhost
uri="mongodb://localhost:27017,localhost:27018,localhost:27019/?replicaSet=replset"
m="mongo $uri --eval" 
sleep 5
$m "db.mycoll.insert({a:1})"

# copy one of the nodes to 2 new locations
rm -rf newrepl
mkdir newrepl
cp -R repl3/replset/rs2 newrepl/rs1
cp -R repl3/replset/rs2 newrepl/rs2

# start both standalones using the copies
mongod --dbpath newrepl/rs1/db --logpath newrepl/rs1/mongod.log --port 28017 --fork --wiredTigerCacheSizeGB 1
mongod --dbpath newrepl/rs2/db --logpath newrepl/rs2/mongod.log --port 28018 --fork --wiredTigerCacheSizeGB 1

dropLocal="db = db.getSiblingDB('local'); db.dropDatabase(); db = db.getSiblingDB('admin'); db.shutdownServer()"

# drop the local database
mongo --port 28017 --eval "$dropLocal"
mongo --port 28018 --eval "$dropLocal"

# startup repl1 as a new replica set
mongod --dbpath newrepl/rs1/db --logpath newrepl/rs1/mongod.log --port 28017 --fork --wiredTigerCacheSizeGB 1 --replSet newrepl

# run rs.initiate
mongo --port 28017 --eval "rs.initiate()"

rm -rf dump
# dump the local database - including the system.replset collection
mongodump --port 28017 --db local
mongodump --port 28017 --db local --collection system.replset

# start the second node as a standalone and restore the local database
mongod --dbpath newrepl/rs2/db --logpath newrepl/rs2/mongod.log --port 28018 --fork --wiredTigerCacheSizeGB 1

mongorestore --port 28018 --db local dump/local

#shutdown the second node
mongo --port 28018 --eval "db = db.getSiblingDB('admin'); db.shutdownServer()"

# to prove that the initial sync does not happen, add a collection that will not exist in the second node once it is joined as a replica set 
# mongo --port 28017 --eval "db.phantom.insert({text: 'only exists in 28017'})"

# start the second node with the replset newrepl
mongod --dbpath newrepl/rs2/db --logpath newrepl/rs2/mongod.log --port 28018 --fork --wiredTigerCacheSizeGB 1 --replSet newrepl

# connect to the first node and run rs.add
mongo --port 28017 --eval "rs.add('Arnies-MacBook-Pro.local:28018')"