※古い情報です。

# vi /etc/yum.repos.d/10gen.repo

64bit

[10gen]
name=10gen Repository
baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/x86_64
gpgcheck=0
enabled=1

32bit

[10gen]
name=10gen Repository
baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/i686
gpgcheck=0
enabled=1

# yum -y install mongo-10gen mongo-10gen-server

# vi /etc/mongod.conf 

# mongo.conf

#where to log
logpath=/var/log/mongo/mongod.log

logappend=true

# fork and run in background
fork = true

#port = 27017

dbpath=/var/lib/mongo

# location of pidfile
pidfilepath = /var/run/mongodb/mongod.pid

# Disables write-ahead journaling
# nojournal = true

# Enables periodic logging of CPU utilization and I/O wait
#cpu = true

# Turn on/off security.  Off is currently the default
#noauth = true
#auth = true

# Verbose logging output.
#verbose = true

# Inspect all client data for validity on receipt (useful for
# developing drivers)
#objcheck = true

# Enable db quota management
#quota = true

# Set oplogging level where n is
#   0=off (default)
#   1=W
#   2=R
#   3=both
#   7=W+some reads
#diaglog = 0

# Ignore query hints
#nohints = true

# Disable the HTTP interface (Defaults to localhost:27018).
#nohttpinterface = true

# Turns off server-side scripting.  This will result in greatly limited
# functionality
#noscripting = true

# Turns off table scans.  Any query that would do a table scan fails.
#notablescan = true

# Disable data file preallocation.
#noprealloc = true

# Specify .ns file size for new databases.
# nssize = <size>

# Accout token for Mongo monitoring server.
#mms-token = <token>

# Server name for Mongo monitoring server.
#mms-name = <server-name>

# Ping interval for Mongo monitoring server.
#mms-interval = <seconds>

# Replication Options

# in replicated mongo databases, specify here whether this is a slave or master
#slave = true
#source = master.example.com
# Slave only: specify a single database to replicate
#only = master.example.com
# or
#master = true
#source = slave.example.com

# chkconfig mongod on

# /etc/rc.d/init.d/mongod start|stop|status

MongoDBの起動に失敗する

# /etc/rc.d/init.d/mongod start
Starting mongod: about to fork child process, waiting until server is ready for connections.
all output going to: /var/log/mongo/mongod.log
forked process: 1409
ERROR: child process failed, exited with error number 100
                                                           [FAILED]

ログを見ていると以下のようなエラーが

# less /var/log/mongo/mongod.log

～
[initandlisten] ERROR: Insufficient free space for journal files
[initandlisten] Please make at least 3379MB available in /var/lib/mongo/journal or use --smallfiles
～

journal filesの作成領域の空き容量が足りないとのことなので、あきらめてjournal filesを作らない。

# vi /etc/mongod.conf 

～
-) # nojournal = true
+) nojournal = true
～

起動成功

# /etc/rc.d/init.d/mongod start
Starting mongod: about to fork child process, waiting until server is ready for connections.
all output going to: /var/log/mongo/mongod.log
forked process: 1425
child process started successfully, parent exiting
                                                           [  OK  ]