Purpose

OMK customers may wish to upgrade MongoDB to 3.2 and realize the efficiencies of Wired Tiger. This example uses CentOS because this is the prevailing Linux distribution used by our customer base.

Steps

Stop running services
Backup Current Database
Install MongoDB 3.2
Provision MongoDB 3.2
Convert to Wired Tiger
Restore services

Procedure

Stop Running Services and Disable opflowd

[root@opmantek ~]# service opconfigd stop
Stopping opconfig daemon opconfigd                         [  OK  ]
[root@opmantek ~]# service opeventsd stop
Stopping opevents daemon opeventsd                         [  OK  ]
[root@opmantek ~]# service omkd stop
Stopping Opmantek Webserver opmantek.exe                   [  OK  ]
[root@opmantek ~]# service mongod stop
Stopping mongod:                                           [  OK  ]
[root@opmantek ~]# service opflowd stop
Shutting down flowd:                                       [  OK  ]

### disable opflowd
[root@opmantek ~]# chkconfig opflowd off

Backup Current Database

Install MongoDB 3.2

Update MongoDB Repository File

In order to install Mondgo3.2 edit /etc/yum.repos.d/mongod-org.repo to reflect the correct version.

/etc/yum.repos.d/mongod-org.repo

### change below to 3.2
[mongodb-org-3.2]
name=MongoDB Repository
### change below to 3.2
baseurl=https://repo.mongodb.org/yum/redhat/\$releasever/mongodb-org/3.2/x86_64/
gpgcheck=0
enabled=1

Install MongoDB 3.2 with yum

[root@opmantek ~]# yum install mongodb-org

Provision MongoDB 3.2

Check what kinds of MongoDB configuration files are in /etc

[root@opmantek etc]# ls -l | grep mongo
-rw-r--r--   1 root root    1564 2015-09-11 10:00 mongod.conf
-rw-r--r--   1 root root     768 2017-02-02 02:07 mongod.conf.rpmnew

If there is one called mongodb.conf it is no longer necessary. Please move this to /root to avoid any future confusion.

Make a backup of the old mondgod.conf and copy the new rpm version over it.

[root@opmantek etc]# cp mongod.conf mongod.conf.backup

[root@opmantek etc]# cp mongod.conf.rpmnew mongod.conf

Provision MongoDB

Now make the following changes to mongod.conf

Change the dbPath to /data/mongodb
Provision wiredTiger
- Uncomment
- Add engineConfig, cacheSizeGB: 8

/etc/mongod.conf

--snip

# Where and how to store data.
storage:
  dbPath: /data/mongodb
  journal:
    enabled: true
#  engine:
#  mmapv1:
wiredTiger:
  engineConfig:
    cacheSizeGB: 8

--snip

Delete temporary files associated with MongoDB

Remove any files in /tmp that look be be associated with MongoDB

If there is a mongod.pid file in /var/run/mongodb, then remove it.

If there is a /data/mongodb/mongod.lock file, then remove it.

[root@opmantek ~]# chown -R mongod:mongod /data/mongodb/

DRAFT - Uprading to MongoDB 3.2 Using Wired Tiger