Mongodb on Rhel

MongoDB on Red Hat Enterprise Linux


Sandeep Parikh
Technical Product Manager
10gen
Sanjay Rao
Principal Performance Engineer
Red Hat

MongoDB on Red Hat Enterprise Linux May 2012


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Table of Contents
Introduction ....................................................................................................................... 3
About Red Hat Enterprise Linux ....................................................................................... 3
About MongoDB ............................................................................................................... 4
MongoDB Components ................................................................................................. 4
Deployment Architectures ............................................................................................. 5
MongoDB on Red Hat Enterprise Linux ........................................................................... 7
Installing MongoDB ....................................................................................................... 7
Storage Configuration ................................................................................................... 8
Securing MongoDB ..................................................................................................... 11
Database Backups ...................................................................................................... 13
System Monitoring ...................................................................................................... 14
Summary ........................................................................................................................ 16


MongoDB on Red Hat Enterprise Linux May 2012


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Introduction
Red Hat Enterprise Linux (RHEL) powers mission critical applications for thousands of
enterprises and delivers performance, reliability, scalability, and security. Certified by the leading
hardware and software vendors, it is suitable for, and has been deployed on, desktops, servers,
and mainframes. It has also completed the most stringent government security certifications,
safeguarding systems and data. RHEL features virtualization, mandatory access control (MAC)
security, high-availability clustering, modularity, and extensive energy management capabilities.

MongoDB is a scalable, high-performance, open source data store. MongoDB provides JSON-
style document-oriented storage with full index support, auto-sharding, sophisticated replication,
and compatibility with the Map-Reduce paradigm. MongoDB focuses on flexibility, power,
speed, and ease of use.

This whitepaper will help you understand the steps necessary to deploy MongoDB on Red Hat
Enterprise Linux 6.2 and take advantage of several features of the underlying system. We will
provide an overview of MongoDB and discuss several example deployment scenarios to support
high performance database reads and writes. We will also review the specific steps necessary
for deploying MongoDB on RHEL 6.2, including tuning system parameters for performance,
reliability and security. The supplied architectural patterns and system configuration steps can
serve as a basis for deploying multi-node database clusters in a production environment.
About Red Hat Enterprise Linux
Red Hat Enterprise Linux is built to support mission critical applications and focuses on
delivering security, reliability and performance for systems on which it is deployed.

The features available in RHEL allow it to meet evolving data center needs. Advances in system
efficiency lead to higher performance as well as reduced operating costs. Increased scalability
meets the need for larger systems with more CPU sockets and cores, more memory, and larger
filesystems. System evolution that makes the most of emerging hardware features such as
Reliability, Availability, Serviceability (RAS) capabilities keeps your systems running in the face
of hardware failures that would have caused previous generations of system to crash.

The primary responsibility of an operating system is to manage processing, memory, storage,
and network resources, RHEL builds on this responsibility with advanced resource management
features. Partitioning processing resources to applications with Control Groups and associated
controllers can help those applications meet SLA, reduce resource bottlenecks, and increase
net system performance. Management of storage and networks includes availability and
performance improvements.

MongoDB on Red Hat Enterprise Linux May 2012


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RHEL also provides a complete portfolio of security technologies with solutions for all facets of
your system, data, and communications security challenges. A secure system depends on
controlling access to services and data, and features from Red Hat’s SELinux have been
applied to more system services, and can be used to run untrusted applications without risk to
your system. Overall system security is improved by standardized deployment documentation
that verifies patch installation and detects possible system compromises. Many improvements
to system identity services include a new service that can aggregate, normalize, and cache
information from diverse identity servers.
About MongoDB
MongoDB is a scalable, high-performance, open source NoSQL database. MongoDB is built
around storing JSON-style documents, allowing data to be schema free and more dynamically
represented. It offers full index support on any attribute which makes queries fast and flexible
and supports atomic in-place document updates for high performance consistent updates.
MongoDB is built from the ground up to scale for high performance database access. High
availability and read scaling are accomplished via Replica Sets, an asynchronous data
replication mechanism where data is written to master nodes and replicated to any number of
secondary nodes. Applications can be configured to read from the primary or any of the
secondaries, providing support for high performance reads. MongoDB also scales horizontally
by automatically partitioning your data across multiple shards without a single point of failure.
Routing requests to the appropriate shard is handled by MongoDB internal mechanisms so that
applications can take advantage of performance increases without being updated and
redeployed.
MongoDB Components
mongod
Mongod is the primary component of MongoDB, responsible for the structured storage system.
In single node or replica set deployments the only component running is mongod. When
deploying sharded configurations, mongos and config will also be necessary.

mongos
Mongos is a routing and coordination process that makes the mongod nodes in the cluster look
like a single system. Mongos processes route data requests, keeping a cached copy of config
server information in memory. Any changes that occur on the config servers are propagated to
each mongos process. Mongos processes may be run on the shard servers themselves, but
they are lightweight enough to exist on each application server. Many mongos processes can be
run simultaneously since these processes do not coordinate between one another.

config
Config server is a mongod process used to synchronously replicate the state information of a
sharded environment. In a sharded environment, config servers store the metadata of the
MongoDB on Red Hat Enterprise Linux May 2012


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cluster. Although the config server can run as a standalone, production deployments should run
three individual config server instances with copies of the same metadata (for data safety).
Deployment Architectures
Using upon these components, the following diagrams illustrate the architecture of various
deployment types. Beginning with a single node, the following steps and diagrams can be used
to guide you through a production deployment as the scale of the database load grows. The
following should be used as reference designs, or starting points, for your own deployment.
Mongod primary and secondary nodes are configured in a similar fashion, which allows replica
set deployments to be completed quickly. Sharded configurations require the additional
configuration of mongos routers and mongod metadata config instances. For more information
about deployment configurations, refer to the MongoDB Replica Set
1
or MongoDB Sharding
2

documentation.

Single MongoDB node
! The basic building block for all other configurations
! Not intended for production use as it as introduces single point of failure



1
http://www.mongodb.org/display/DOCS/Replica+Sets
2
http://www.mongodb.org/display/DOCS/Sharding
MongoDB on Red Hat Enterprise Linux May 2012


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Multi-node replica set
! Requires an odd number of nodes (for primary election purposes)
! Replica sets are used for data redundancy
! Apps can also be updated to read from secondary nodes, supporting read scaling


Spreading a replica set across datacenters
! Ensures high availability access to data even if an entire data center is lost


MongoDB on Red Hat Enterprise Linux May 2012


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Sharding using replica sets as the base for each data shard
! Config servers manage metadata for sharded configurations (shard keys, data
balancing)
! Mongos routes requests from applications to the correct data shard

MongoDB on Red Hat Enterprise Linux
Installing MongoDB
To get started with MongoDB, first complete the installation and setup for a base Red Hat
Enterprise Linux server system. Depending on the type of installation completed, you may need
to add an additional group and administrative-level user (if they weren’t created during
installation). You will also need to register the system with Red Hat in order to use package
management utilities and receive system updates. For more information, refer to the RHEL
Product Subscriptions and Entitlements
3
documentation.

The steps documented below show how to configure a single MongoDB instance. These steps
can be used for every MongoDB node in your cluster, whether deploying a single instance or
replica set or sharded configuration. Before continuing, confirm that !!"# is running, this is how
we’ll access the nodes in our cluster once deployed (outside of MongoDB processes).

$ !&#' !()*+,( !!"# !-.-&!


3
http://docs.redhat.com/docs/en-
US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/entitlements.html
MongoDB on Red Hat Enterprise Linux May 2012


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If !!"# is not running, go ahead and start it up

$ !&#' !()*+,( !!"# !-.)-

Once the system is setup, we can proceed with installing MongoDB. The first step is to add a
10gen repository to /&0:

$ (,"' 12345(67
6.0(8345(6 9(:'!+-')/
;.!(&)<8"--:=>>#'?6<'.#!@#+!-)'A0'65'#;A')5>)(:'>)(#".->'!>BCDEDF
5:5,"(,G841 H !&#' -(( @. >(-,>/&0A)(:'!A#>345(6A)(:'

Next, install the latest version of MongoDB and !/!!-.- utilities:

$ !&#' /&0 @/ +6!-.<< 0'65'@345(6@!()*()
$ !&#' /&0 @/ +6!-.<< !/!!-.-

Now edit the 0'65'# configuration file and set the following properties:

$ 6.6' >(-,>0'65'#A,'6I
J
K'&)6.<8-)&(
#;:.-"8>#.-.
<'5:.-"8>#.-.><'5>0'65'#A<'5
J

Depending on your configuration, you may also want to configure ':<'5L+M( in mongod.conf.
MongoDB Replica Sets use an operation log (oplog) to store write operations, which are then
relayed asynchronously to the secondary nodes in the set. By default, the ':<'5L+M( parameter
is set to be equivalent to 5% of the disk space. Generally, this is a reasonable start but can be
configured over time based on your deployment. For more information, refer to the MongoDB
Replica Sets Oplog
4
documentation.
Storage Configuration
At this point MongoDB has been installed, but before we start the service we must configure the
data storage (#;:.-" parameter above). There are several options to consider when configuring
database storage including volume arrangement, filesystem and encryption.
Volume Management
With volumes, you have a choice between using logical volumes (which map to multiple physical
volumes) or using a RAID configuration (hardware or software-based). Logical volumes (LVM)

4
http://www.mongodb.org/display/DOCS/Replica+Sets+-+Oplog
MongoDB on Red Hat Enterprise Linux May 2012


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allow you to map multiple physical volumes to a single logical device, with options for striping or
mirroring data across the physical devices. For more information on LVM refer to the RHEL
Logical Volume Manager
5
documentation. The recommended approach is to use a RAID10 disk
configuration, which is a combination of RAID0 (striping) and RAID1 (mirroring). This
configuration typically provides the best combination of performance and reliability. To setup
software-based RAID10 storage, install and use the 0#.#0 tools to configure the volumes.

$ !&#' /&0 +6!-.<< 0#.#0
$ !&#' 0#.#0 @@,)(.-( @<34 @6F >#(*>0#4 >#(*>!#.N

This example shows how 4 (@6F) physical volumes attached to the system (e.g. >#(*>!#.3,
>#(*>!#.O, >#(*>!#.P, >#(*>!#.F) can be configured to use RAID10 (@<34). Once mdadm
has completed you can create a filesystem and mount the device.
Filesystems
When using RHEL there are two choices of recommended filesystems, ext4 or XFS. Ext4 uses
extents, which improves performance when using large files and reduces metadata overhead for
large files. In addition, ext4 also labels unallocated block groups and inode table sections
accordingly, which allows them to be skipped during a file system check. This makes for quicker
file system checks, which becomes more beneficial as the file system grows in size. XFS is a
scalable, high performance filesystem created to support extremely large filesystems. XFS
supports metadata journaling, which facilitates quicker crash recovery. The XFS file system can
also be defragmented and enlarged while mounted and active. In addition, RHEL supports
backup and restore utilities specific to XFS. Note: RHEL also supports the ext3 filesystem,
however it is not recommended for use with MongoDB due to issues with file allocation and
large file access.

To create an ext4 filesystem on a new device (ex. >#(*>0#4), use the following command:

$ !&#' 0GI!A(B-F >#(*>0#4

For XFS, use the following:

$ !&#' 0GI!ABI! >#(*>0#4

After creating the filesystem we’ll add an entry to the filesystem table to use when mounting the
device. The following command adds an entry to >(-,>I!-.; for the storage device >#(*>0#4
and a mount point >#.-. along with information about the filesystem we’re using (ext4 or XFS)
and a number of mount options that are recommended for MongoDB data storage
(#(I.&<-!Q.&-'Q6'.-+0(Q6'(B(,).

5
http://docs.redhat.com/docs/en-
US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/ch-lvm.html
MongoDB on Red Hat Enterprise Linux May 2012


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Using ext4:
$ (,"' R>#(*>0#4 >#.-. (B-F #(I.&<-!Q.&-'Q6'.-+0(Q6'(B(, 4 4S H !&#' -(( @.
>(-,>I!-.;

Or using XFS:
$ (,"' R>#(*>0#4 >#.-. BI! #(I.&<-!Q.&-'Q6'.-+0(Q6'(B(, 4 4S H !&#' -(( @.
>(-,>I!-.;

With that complete, we can continue setting up the rest of the data storage. First create the
mount point >#.-. and then mount the storage device:

$ !&#' 0G#+) >#.-.
$ !&#' 0'&6- >#(*>0#4

Set the ownership of the mount point to the MongoDB user (0'65'#) and group (0'65'#) that
were created during the package installation:

$ !&#' ,"'?6 0'65'#=0'65'# >#.-.

Now we can start MongoDB, connecting to the system from a local 0'65' client and save a test
document to confirm that storage is functioning as expected:

$ !&#' !()*+,( 0'65'# !-.)-
$ 0'65'
T'65'UV !"(<< *()!+'6= OA4AF
,'66(,-+65 -'= -(!-
W #;A-(!-X'<<(,-+'6A!.*(YZ.=3[\
W #;A-(!-X'<<(,-+'6AI+6#]6(Y\
Z 1E+#1 = ];K(,-^#Y1FIDF;(I#(OO_((_P;_3`O3331\Q 1.1 = 3 [
Storage Encryption
When considering encryption, RHEL provides two options - a pseudo-filesystem that provides
data and filename encryption or whole disk encryption. The key difference between the two
options is whether data is protected while in-use or at-rest. The pseudo-filesystem approach
encrypts data while in-use by adding a secure layer over the mounted device. While mounted (in
use) data on the device is encrypted. Full disk encryption is more appropriate when the desired
approach is to maintain disk encryption after the system has been powered off. Each one has
different use cases, depending upon your deployment considerations one or both may be
appropriate.

MongoDB on Red Hat Enterprise Linux May 2012


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The first option requires little setup; by issuing an additional mount command (before starting
0'65'#) the pseudo-filesystem eCryptFs is configured and mounted (configuration occurs upon
initial launch):

$ !&#' 0'&6- @- (,)/:-I! >#.-. >#.-.

Note, the last two arguments (source and destination) are the same, this ensures that any
access to >#.-. is encrypted and consistency between secured content is maintained.

If you are interested in setting up at-rest full disk encryption you’ll need to perform additional
steps. Linux Unified Key Setup-on-disk-format (or LUKS) allows you to encrypt partitions on
your system, refer to the RHEL LUKS Disk Encryption
6
documentation for more information.

We have completed the setup and installation of MongoDB. The above steps should be
repeated on each node in your cluster, regardless of whether you are setting up a replica set or
sharded deployment.
Securing MongoDB
With the initial setup complete, we now focus on securing the system. To secure the server, we
will utilize two mechanisms built into RHEL, TCP Wrappers and Netfilter. For network services
that utilize it, TCP Wrappers add an additional layer of protection by defining which hosts are or
are not allowed to connect to "wrapped" network services. Netfilter, controlled by the iptables
administration tool, provides stateful and stateless packet filtering as well as routing and
connection state management. Using one or both of these mechanisms can help safeguard your
servers. Use of these services is optional but highly recommended when deploying production
systems.

To use TCP Wrappers, a service must either be compiled with support for it or be managed by a
“wrapped” process. With MongoDB the latter approach should be used, with the 0'65'#
process controlled via B+6(-#, a super-server daemon that manages networked services such
as FTP or Telnet. When a client attempts to connect to a network service controlled by B+6(-#,
the super service receives the request and checks for any TCP Wrappers access control rules.
For more information on how to configure and use this approach, refer to the RHEL TCP
Wrappers and B+6(-#
7
documentation

To use Netfilter, we’ll create IP filtering rules using the iptables admin tool. This will allow us to
specify port and protocol level access. By default the server is setup to only accept connections

6
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-
Security_Guide-LUKS_Disk_Encryption.html
7
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-
Security_Guide-TCP_Wrappers_and_xinetd.html
MongoDB on Red Hat Enterprise Linux May 2012


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via SSH and we’ll be adding rules to cover all of MongoDB’s common ports. The specific ports
are
" 27017 - MongoDB core process (mongod)
" 27018 - MongoDB shard server (mongos)
" 27019 - MongoDB config server (mongod)
" 28017 - MongoDB web-based statistics interface (this defaults to the port that mongod
uses plus 1000)

Depending on your deployment, it may be necessary to restrict access to the server and only
allow connections from specific addresses. The following commands show an example rule for
the 0'65'# core process (port 27017) with additional examples of how to add rules for each of
MongoDB ports.

$ !&#' +:-.;<(! @a ^bcde @0 !-.-( @@!-.-( bfgQfLeaVh^LifU @! 3_OA3DCABA/ @:
-,: @@#:')- O`43` @K aXXfce

If your deployment will include sharding, then the following examples rules can be used to open
up the required ports:

$ !&#' +:-.;<(! @a ^bcde @0 !-.-( @@!-.-( bfgQfLeaVh^LifU @! 3_OA3DCABA/ @:
-,: @@#:')- O`43C @K aXXfce
$ !&#' +:-.;<(! @a ^bcde @0 !-.-( @@!-.-( bfgQfLeaVh^LifU @! 3_OA3DCABA/ @:
-,: @@#:')- O`43_ @K aXXfce

Finally, to enable access to the web-based status interface:

$ !&#' +:-.;<(! @a ^bcde @0 !-.-( @@!-.-( bfgQfLeaVh^LifU @: -,: @@#:')-
OC43` @K aXXfce

After the rules have been added, save the +:-.;<(! rules to persist them to disk:

$ !&#' !()*+,( +:-.;<(! !.*(
+:-.;<(!= L.*+65 I+)(?.<< )&<(! -' >(-,>!/!,'6I+5>+:-.;<(!=2 ]j 7

The rules we’ve added allow incoming connections to all ports needed for MongoDB from any
incoming address that is in the 3_OA3DCABA/ block. Depending upon your cluster configuration,
it may be necessary to supply arguments to restrict access from specific sources (for example,
@! kkAkkAkkA4>OF only allows access from sources located on the same subnet). In addition
to setting the source address when using +:-.;<(! firewall rules, it is also important to set the
;+6#E+: parameter in the MongoDB configuration file. This will cause MongoDB to only listen
on a specific address when accepting incoming connections. The examples above will need to
MongoDB on Red Hat Enterprise Linux May 2012


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be amended for your deployment, refer to the RHEL Security Guide on IPTables
8
for more
information.
Database Backups
Depending upon the configuration if your server(s), there are multiple ways to backup the data
stored in MongoDB. One options is a volume-specific backup, where the database is issued an
“fsync+lock” command, which locks the system from incoming writes, then backups are
conducted and the database is unlocked. Note, this approach should only be used with a
secondary node within a replica set (or within a replica set inside of a shard) in order to prevent
errors in your app when attempting to write data.

First connect to a secondary server (as noted in the mongo prompt LfX]bUa9lW), switch to the
admin database and issue the lock command:

$ 0'65'
T'65'UV !"(<< *()!+'6= OA4AF
,'66(,-+65 -'= -(!-
LfX]bUa9lW &!( .#0+6
!?+-,"(# -' #; .#0+6
LfX]bUa9lW #;AI!/6,h',GY\
Z
1+6I'1 = 16'? <',G(# .5.+6!- ?)+-(!Q &!( #;AI!/6,d6<',GY\ -' &6<',G1Q
1!((a<!'1 = 1"--:=>>???A0'65'#;A')5>#+!:<./>U]XL>I!/6,mX'00.6#1Q
1'G1 = 3
[

While the database is locked, conduct any backups of the volume or the directory where
MongoDB stores data files. Once those backup operations are completed, unlock the database
so that writes may be accepted once again:

LfX]bUa9lW #;AI!/6,d6<',GY\
Z 1'G1 = 3Q 1+6I'1 = 1&6<',G ,'0:<(-(#1 [

If you’re data storage was configured to use the XFS filesystem, RHEL includes filesystem-level
utilities that can be used for backups. The BI!#&0: command conducts backups or dumps of
active XFS filesystems to another storage device. The command also includes the ability to
conduct incremental backups by specifying backup levels. For more information, refer to the
BI!#&0: man page
9
.

If the data storage was configured using the logical volume manager (LVM) another option is to
use LVM snapshots. LVM supports the creation of snapshot volumes from existing logical
volumes. This allows you to run backup operations on the snapshot without disturbing the active

8
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-
Security_Guide-IPTables.html
9
http://linux.die.net/man/8/xfsdump
MongoDB on Red Hat Enterprise Linux May 2012


14
logical volume. If MongoDB has been configured to use journaling (on by default) and if the
journal files are also on the volume being snapshotted, then there is no need to “fsync+lock” the
database before taking an LVM snapshot.

Another option is to use one of MongoDB’s internal tools T'65'#&0:, which can be used to
backup specific collections, databases or all data. Paired with a ,)'6 job, 0'65'#&0: can be set
to run on a regular basis to conduct full data backups. An example backup script could take the
form of the following:

no>;+6>;.!"
!&II+B8$Y#.-( mp?\
0G#+) >"'0(>&!()6.0(>;.,G&:>0'65'@$!&II+B
>&!)>;+6>0'65'#&0: @' >"'0(>&!()6.0(>;.,G&:>0'65'@$!&II+B

This script uses the current date in the backup directory name and saves all data from the
MongoDB database in the specified directory. To run this script every night at 12am use the
,)'6-.; utility:

$ ,)'6-.; @(

And add the following line:

4 4 N N N >;+6>;.!" >:.-">-'>;.,G&:>!,)+:-A!"

For more information configuring ,)'6 jobs, refer to the ,)'6-.;
10
documentation. T'65'#&0:
can be used with single instances, replica sets or sharded configurations. In the latter two
deployment scenarios, there are additional parameters
11
required to ensure consistent backups,
which are documented on the MongoDB site.

For more information about backing up data or details about advanced configurations, refer to
the MongoDB Backups
12
documentation.
System Monitoring
MongoDB and RHEL include several tools to help monitor the performance of your database
instances. MongoDB includes 0'65'!-.- (exposes internal system metrics), a query profiler
and diagnostic tools (via the 0'65' shell). 10gen also offers MongoDB Monitoring Service,
which is a free SaaS solution for proactive monitoring of your MongoDB cluster. MMS requires
minimal setup and can be deployed onto your cluster quickly. To learn more about MMS, refer to

10
http://crontab.org/
11
http://www.mongodb.org/display/DOCS/Import+Export+Tools - ImportExportTools-mongodump
12
http://www.mongodb.org/display/DOCS/Backups
MongoDB on Red Hat Enterprise Linux May 2012


15
the 10gen MongoDB Monitoring Service
13
site. For more information about MongoDB monitoring
tools, refer to the MongoDB Monitoring and Diagnostics
14
documentation.

Outside of MongoDB, there are several system utilities that can be used to report system
resource usage. For monitoring CPU utilization in predefined intervals you can use !.), which
allows you to collect and report system activity information. Similar to !.), +'!-.- provides
statistics about CPU usage, devices, partitions and network filesystems. For monitoring memory
usage, *0!-.- provides information about processes, memory, paging and block I/O.

In addition, RHEL also provides dynamic resource management via Tuned and G-&6(. Tuned is
a daemon that monitors the use of system components and dynamically tunes system settings
based on that monitoring information. Dynamic tuning accounts for the way that various system
components are used differently throughout the uptime for any given system. For example, the
hard drive is used heavily during startup and login, but is barely used later. Tuned monitors the
activity of these components and reacts to changes in their use.

To get started, first install the Tuned package via yum:

$ !&#' /&0 +6!-.<< -&6(#

Next use the -&6(#@.#0 command to activate the “throughput-performance” tuned profile. This
profile adjusts the system settings to optimize for high throughput applications. Specifically, it
disables tuned and ktune power saving mechanisms, enables sysctl settings that improve the
throughput performance of your disk and network I/O, and switches to the deadline scheduler.
The built-in profiles are also intended to be a starting point; if you are interested in further
system optimizations, duplicate the current profile (available in >(-,>-&6(@:)'I+<(!) and
adjust its settings:

$ !&#' ,: @. >(-,>-&6(@:)'I+<(!>-")'&5":&-@:()I')0.6,( >(-,>-&6(@
:)'I+<(!>0/:)'I+<(

Inside the newly created profile, the following four files contain system optimization settings.
Review and edit these files as needed to optimize the system to your specifications.

tuned.conf
The configuration for the -&6(# service to be active for this profile.
sysctl.ktune
The !/!,-< settings used by G-&6(. The format is identical to the
>(-,>!/!,'6I+5>!/!,-< file (refer to the !/!,-< and !/!,-<A,'6I man pages).

13
http://www.10gen.com/mongodb-monitoring-service
14
http://www.mongodb.org/display/DOCS/Monitoring+and+Diagnostics
MongoDB on Red Hat Enterprise Linux May 2012


16
ktune.sysconfig
The configuration file of ktune itself, typically >(-,>!/!,'6I+5>G-&6(.
ktune.sh
An init-style shell script used by the ktune service which can run specific commands
during system startup to tune the system.

Another tool available in RHEL is SystemTap, an application profiler. It is a tracing and probing
tool that allows users to study and monitor the activities of the operating system (particularly, the
kernel) in fine detail. It provides information similar to the output of tools like 6(-!-.-, :!, -':,
and +'!-.-; however, SystemTap is designed to provide more filtering and analysis options for
collected information. It is most useful when other similar tools cannot precisely pinpoint a
bottleneck in the system, requiring a deep analysis of system activity.

To get started with SystemTap, install support for it via /&0:

$ !&#' /&0 +6!-.<< !/!-(0-.: !/!-(0-.:@)&6-+0(

The RHEL SystemTap Beginners Guide
15
contains links to several useful SystemTap scripts.
For MongoDB, possible areas to examine include system networking and disk I/O. The scripts
for network profiling
16
and summarizing disk traffic
17
could be used as a starting point for
analyzing system performance. Refer to the SystemTap guides and wiki
18
for more information
on performance analysis and reporting.
Summary
Red Hat Enterprise Linux provides a robust platform for deploying MongoDB. With features and
functionality that emphasize security, reliability and performance, RHEL enables you to deploy
MongoDB instances that can meet production needs.

For more information about MongoDB, see http://www.mongodb.org

For more information about Red Hat Enterprise Linux, see
http://www.redhat.com/products/enterprise-linux/


15
http://docs.redhat.com/docs/en-
US/Red_Hat_Enterprise_Linux/6/html/SystemTap_Beginners_Guide/index.html
16
http://docs.redhat.com/docs/en-
US/Red_Hat_Enterprise_Linux/6/html/SystemTap_Beginners_Guide/useful-systemtap-scripts.html -
nettopsect
17
http://docs.redhat.com/docs/en-
US/Red_Hat_Enterprise_Linux/6/html/SystemTap_Beginners_Guide/mainsect-disk.html - disktop
18
http://sourceware.org/systemtap/wiki/HomePage