MongoDB

Configuration

• Params https://docs.mongodb.com/manual/reference/parameters/#param.maxTransactionLockRequestTimeoutMillis
• Config https://docs.mongodb.com/v3.2/reference/replica-configuration/#rsconf.settings.electionTimeoutMillis

Installer

• Install older version

rpm -e --noscripts mongodb-org-server-3.2.21-1.el7.x86_64
yum list mongodb-org* --showduplicates
yum install mongodb-org-3.2.19

Tunning

• Kernel

• Block Device

Common Ops

Replica Set

• States: https://docs.mongodb.com/manual/reference/replica-states/

• Check status

• Change rset config

Eg. change the prio of the member

cfg = rs.conf()
cfg.members[1].priority = 1.5
cfg
rs.reconfig(cfg)
rs.status()

• change oplog size

https://docs.mongodb.com/v3.2/tutorial/change-oplog-size/

• Check collections config

mongos> db.getSiblingDB("config").collections.find();

mongo --quiet --eval 'var c = db.getSiblingDB("config").collections.find(); c.forEach(printjsononeline)'

Shutdown

• on the slaves

use admin
db.shutdownServer()

• on the master [last]

rs.stepDown(300)

Cheat Sheet

currentOp

https://hackernoon.com/mongodb-currentop-18fe2f9dbd68

`shutdown'

https://docs.mongodb.com/manual/tutorial/manage-mongodb-processes/#use-shutdownserver

use admin
db.shutdownServer()

Shards

• References

https://docs.mongodb.com/manual/core/sharded-cluster-shards/

MISC

• https://docs.mongodb.com/manual/tutorial/deploy-geographically-distributed-replica-set/