Splunk best practices

Aplura, LLC
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Focused Information Security
www.aplura.com
Splunk Best Practices
The recommendations in this document were compiled by Aplura's staff over their many years of Splunk
administration and professional services engagements. Many of these items come up time and time again
during engagements and consideration of these items will result in a more successful implementation. A
successful implementation is one that is efficient, scalable, follows information security best-practice, and
is, most importantly, useful.
Although everything here is valuable, some of it does not apply for very small or specific implementations
of Splunk. Largely, most of this applies to most environments we see.
Table of Contents
Common Splunk Topology...............................................................................................................................2
Architecture and Design................................................................................................................................... 2
Hardware...........................................................................................................................................................4
Data Routing.....................................................................................................................................................6
Inputs................................................................................................................................................................ 6
Syslog Input......................................................................................................................................................6
High Performance Syslog........................................................................................................................... 7
Application or Data Specific............................................................................................................................ 7
Forwarder Deployment.....................................................................................................................................9
Windows Deployment.................................................................................................................................9
Linux Deployment...................................................................................................................................... 9
Performance....................................................................................................................................................10
Search Help.....................................................................................................................................................10
Storage and Data Management.......................................................................................................................10
Deployment Server......................................................................................................................................... 11
App Development...........................................................................................................................................11
Analytics.........................................................................................................................................................12

Common Splunk Topology
This architecture has several key components such
as:
• Multiple Intermediate Heavy Forwarders
for increased load, High Availability, and
improved speed of processing in coming
events
• An Indexer tier of multiple systems.
Multiple search-peers (indexers) improves
performance both during data-ingest and
search. This strategy reduces search time
and provides some redundancy of data-
ingest should a single server fail
• One or more separate search heads. This
separate system will distribute any search
request across all configured search-peers
improve search performance.
• A separate search head is shown here to
support Splunk's Enterprise Security (ES)
application
• Deployment Server. This system can be
collocated with other Splunk services, or
stand-alone. For large deployments, a
stand-alone system is important.
Architecture and Design
• Plan indexes and sourcetypes. These two things will be difficult to change later. Indexes and
sourcetypes assist in data management. See Defaultfield and Indexed Fields
• Use sourcetypes to group data by their similarity. If the events are generated by the same device
and are in the same format, they should most likely be one sourcetype. See this great blog-post on
Sourcetype naming.
• Try to collect events as close (in terms of geography and network location) as possible. These
events can be collected with an Intermediate Heavy Forwarder, and then sent to indexers which
may be a central location.
• Try to keep search heads as close to indexers as possible. This will improve the search head's
speed in accessing the events.
• Use separate IP addresses whenever possible. Such as: management, log collection, web UI/search
head and use separate IPs for different major sourcetypes. All of this makes your Splunk
deployment more extensible, provides better access control options, and allows for fine-grained
troubleshooting and analysis
• Use a consistent naming scheme on the Splunk Search Heads, Indexers to ensure accuracy and
reduce troubleshooting time.
• Carefully plan the deployment of Windows event collection (Event logs and Performance data) to
ensure success. Many Windows event collection tools have various limitations such as the
truncation of events at 512 or 1024 bytes. The Splunk Universal Forwarder doesn't have these
limitations and can be used to reliably and efficiently collection Windows events from a large
distributed Enterprise.
• Single team accountability. A single team should be responsible for Splunk instead of having this
split across multiple departments, divisions, or entities. Additionally, much of the deployment of
Splunk requires an intimate understanding of its intended use and therefore it is recommended that
the team who will be the major user of Splunk should also manage its deployment. This generally
equates to a more successful implementation.
• Splunk License Management

◾ PRE-4.2 Use a different Splunk license on each indexer. Re-using a Splunk license
violates the AUP and breaks distributed search as well as other Splunk-to-Splunk activities
◾ POST-4.2 Use a Splunk License Master to control the licensing of your indexers and
don't forget to include you search heads and any heavy/full forwarders in that license.
If you are in a distributed deployment, with multiple Splunk search heads, indexers or forwarders,
strongly consider using Deployment Server. Using deployment server can help keep consistent
configuration across Splunk systems, and make configuration changes much easier (no having to
touch every system).
• Carefully and consistently use Splunk's listening ports which bind to specific back-end processes.
Some of these are referenced when Splunk starts. Generally speaking here are the standard ports,
if they have not been altered:
• tcp/8089 - splunkd - Splunk's daemon port used for distributed search and deployment
server
• tcp/8000 - splunkweb - Splunk's web port used for web UI access
• tcp/9997 - splunktcp listener - Port commonly used to send events from a Splunk
forwarder to a Splunk listener (indexer or another forwarder). Note: This can be any
permissible port, 9997 is just an example.
• Plan your 6.1 migration. There are many new features and enhancements in Splunk 6.1.x and a
migration to it from previous Splunk versions warrant careful consideration and planning.
• Perform integrity checks. Splunk is incredibly precise in how it collects and represents your data;
however, if you send it bogus or duplicate data it may index this as well. Occasionally review your
inputs and ensure your data is accurate, time stamps are good, and there are no mistakes such as
incorrect or duplicated events. There is a Data Onboarding application on Splunk Apps that can
help examine indexes, sourcetypes, hosts, and data models to ensure that your data is being
onboarded correctly.
• Integrate AD for authentication. Splunk integrates fairly well with Active Directory to authenticate
users. This configuration allows you to assign a user to a group in AD then map this group to a
role in Splunk. When this user logs in to Splunk, they are given their specific capabilities and
rights assigned by the role. This is granular RBAC (Role Based Access Controls). The MS AD
tool adsiedit.msc is great to browse an AD domain for valuable items necessary to setup AD auth
on Splunk. This tool is installed by default on 2008 AD systems, but would need to be installed
manually as part of the RSAT package on other versions of Windows.
• Use a separate OU for Active Directory Integration. When configuring AD, you can specify a list
of one or more bindgroupDN for Splunk to look for groups in AD. If you just give the root dir of
all of the groups then Splunk could return hundreds/thousands of Groups. Additionally, if
leveraging existing groups there could be many other users in that group that you don't want to
have access to Splunk. If you created a new base_ou (e.g. OU=splunkgroups) in AD, then create
your access groups under this, e.g. OU=unix_admins,OU=splunkgroups,
OU=network_admins,OU=splunkgroups), then you can set the bindgroupDN to splunkgroups to
minimize returned groups as well as users who have access to Splunk.
• Migrating Index Data. This can be very tricky and you need to be careful since you could destroy
and disable your data. It is advised that you call Splunk support or have PS help you. If you must
do this manually, read and understand the docs and how the bucket structure works, and you can
take a look at this answers post on the subject.
• Avoid parsing raw data on the Indexers. Although the Splunk Indexer is perfectly capable of
parsing raw data sent to it from a Universal Forwarder or a non-Splunk source such as syslog, this
effort could have an undesirable impact on your performance and administrative overhead such as:
• Alleviates parsing load from your Indexer allowing it to focus on indexing and retrieving
events
• Indexers have more code and more components/configurations than Forwarders;
therefore, they are more effected by patches and bug-fixes than Indexers. A simple
forwarder might not need to be patched for months or more, makig it a more stable
platform to receive unreliable syslog data (UDP) with minimal loss.
•
• The Splunk forwarder will store and forward events when the indexer is down (e.g.
during a restart)

• If an Indexer is also parsing raw data, then you will have to maintain all of your parse-
time rules on it as well. Not only are these additional configurations that your Indexer
must parse and hold in memory, but most parse-time configurations require a restart to
make effective, which could mean more frequent restarts of your Indexer. If an Indexer
has to terminate dozens, hundreds or even thousands of TCP sessions from connected
forwarders it could take 10+ minutes for a restart. Multiply by the number of indexers you
have, and a small parsing change could take hours to implement.
• See the item below titled "Intermediate Heavy Forwarder for data ingest" for additional
considerations.
• Intermediate Heavy Forwarder for data ingest. Although end-nodes can send their data directly to
Splunk indexers, in a distributed Splunk environment, an Intermediate Heavy Forwarder provides
many advantages such as:
• Two or more Heavy Forwarders can be used for fault-tolerant ingest of incoming data
• AutoLB (Auto Load-Balance) incoming data across the Splunk Indexers ensuring that
Real-time alerts will never fail due to a single-server outage
• Dedicates systems to the task of collecting the raw-data helping to ensure the data gets
forwarded off of the original system that generated it (e.g. servers with the Universal
Forwarder installed, such as a MS Exchange Server, Oracle Database, MS AD server, or
Intrusion Detection System) as quickly as possible to minimally impact that critical
system.
• Parses the raw data minimizing the work/effort that must be done by the Indexers
• Terminates the TCP connections from the many Universal Forwarders minimizing the
work/effort that must be done by the Indexers. Note, this also has a dramatic effect in the
restart time. Having the Intermediate Heavy Forwarder terminate these sessions and not
the Indexers means that when the Indexers do a restart, they can come back online much
more quickly.
• Provides a more clear/linear flow of data to the Indexers. This could be useful in many
ways but especially to support data collection from a remote location.
• Index-time configuration changes can be applied to the Intermediate Heavy Forwarder
and therefore you are not constantly restarting the Indexers and losing valuable summary
data.
Hardware
• Information: To spec out hardware with Splunk requires more than just a quick guide, but the
following list may help you to get started. This is not intended to replace a scoping discussion with
a Splunk Sales Engineer, but rather to assist a customer in preparation for a professional services
engagement.
• Splunk hardware planning. Answering these three questions will suffice for the average
deployment, but not all deployments.
• Splunk hardware planning: Know what the size/scope of your deployment is. You must
know the amount you expect to index/day. Additionally, you should have a rough idea of
how many Splunk users there will be, and what their intensity/usage will be. Finally, you
should understand your data sources and either their load/volume or the complexity
required to collect data from them.
• Splunk hardware planning: Determine what components you need. Read about Splunk
components to better understand what exists. In general, most deployments would benefit
from having the following:
• (1) Search Head
• (2+) Indexer
• (2+) Heavy Forwarder
• Splunk hardware planning: Determine number of indexers. According to Splunk's
Documentation, a single indexer can accommodate up to about 100GB/day. If you are
processing 100GB/day of data volume for use with Enterprise Security, you will need
approximately 340GB more space available across all of the indexers to allow for up to 1
year of data model retention and source retention. An indexer, when used in an ES

deployment, can accommodate up to 34GB/day. Also note that newer versions of ES
(starting with 3.0) no longer store summary data in TSIDX file on search head, Please
see Splunk's deployment planning documentation for updates to these numbers as they
can vary at times.
• Splunk doesn't prescribe exactly what hardware you must purchase; however, you should read
through the following documentation to better understand their minimum specs:
• High-Level System Requirements
• Hardware Capacity Planning
• CPU Spec. CPU is somewhat varied depending on what component you are talking about. For
indexers, the current sweet spot for servers has been 8-12 core machines (I.e. dual socket quad or
six core boards). Splunk can work with either AMD or Intel architecture on x86 systems.
• Memory Spec. Memory is somewhat varied depending on what component you are talking about.
Generally speaking indexers do particularly well with 16+ GB of memory, meanwhile other
components might require less.
• Scale by adding more Indexers. In a well-configured distributed Splunk environment, you can
scale simply by adding more indexers. The Intermediate Heavy Forwarder can forward data to the
new indexer, and your search heads will request data from the new indexer. Generally speaking,
this scales linearly resulting in a situation where double the indexers cuts the search time in half.
• Methodically plan storage needs for a new deployment, prior to implementation.
• Storage Hardware.
• Drive speed makes a difference. Splunk has informally documented that an increase in
drive-speed will have a dramatic improvement on performance.
• Distributed Architecture. Carefully plan Splunk Distributed Architecture to ensure the
most accurate and efficient processing.
• Storage Needs. Methodically plan storage needs for a new deployment, prior to
implementation.
•
• RAID Level. Use RAID1+0 whenever possible for the Splunk datastore. Little impact
will be seen at low volumes; however, at higher data volumes you will see performance
improvement with RAID1+0 over RAID 5.
• Benchmark storage. Splunk recommends 1200 IOPS (Input/Outputs Per Second) or
better on your storage tier. To get this performance, you will need to be using fast drives
in an optimal RAID configuration served by an efficient controller (either internal, DAS,
or SAN). There are various ways to test your storage to benchmark your current values,
but the mostly commonly used method is via the venerable tool bonnie++ found in the
repository of every major Linux distribution. There are many online guides (even on
Splunk's site) for how to run this tool; however, below is the gist:
• Ensure the target drive to be tested (e.g. /splunk_hot) is mounted and relatively
not in use (meaning stop Splunk if it is running). You want to not use it in order
to get an accurate reading from bonnie++ without competing for resources with
it.
• Next, run the bonnie++ command against the target drive, with a “-s” option
equal to 3-10x the amount of RAM you have in MB
• bonnie++ -d /splunk_hot -s 264000 -u root:root -fb
• If you choose to, you can pipe the above to one of these two commands
(both come with bonnie++): bon_csv2html, bon_csv2txt
• In the output, Random Seeks/s = IOPS
• Architecture type. Splunk works well with both 32 and 64 bit platforms; however, there is a
considerable performance improvement for 64 bit and this should be selected (both for Hardware
and Operating System) whenever possible.

Data Routing
• Information: Data routing allows the Splunk administrator to selectively determine what
incoming data gets ingested, what gets forwarded, and what gets dropped.
• Drop incoming data with the nullQueue. Beware not to go nullQueue-happy and drop too much.
Many events while insignificant by themselves provide useful information when trended or
otherwise analyzed.
• Forward to a Splunk system whenever possible, but if there is a Use Case to send to an external
system, following these instructions to Forward data to third party systems. Beware there are some
caveats of doing this.
• Use Splunk AutoLB (Load Balancing) to distribute data to multiple indexers/forwarders. Much of
this configuration must be done with the outputs.conf file.
Inputs
• Ensure all critical systems have consistent time configuration. Systems generating events should
have the proper time to ensure the events they create will be able to be correlated when analyzed.
Consider NTP use throughout the enterprise as well as frequent time audits of the most critical
systems to ensure accuracy.
• Consider doing regular time-audits. This is where, you evaluate the time of your most
critical systems to ensure they are consistent. If the data is in Splunk, then this task might
just take a few minutes every month or so and is well worth it.
• Explicitly configure Splunk to read time stamp information from incoming events. Splunk's reads
the time stamp from incoming events, which it then associates to the event in the index and the
underlying buckets. It is imperative that time stamps and timezone offsets be parsed and set
correctly both for usability and efficiency purposes.
• Test new inputs. When new inputs will be created, test the data first by ingesting some of it and
determine if it requires adjustments such as for time stamps, event-processing (such as breaking).
• Syslog before Splunk. Traditional syslog technologies (syslogd, syslog-ng, rsyslogd) are simple
and featureless compared to Splunk, but this is their advantage. Since these packages rarely change
and require a small amount of resources, they are perfect for being the initial recipient of syslog
data on the network. When network devices send syslog messages, this data is frequently UDP
(connectionless) and therefore vulnerable in-transit. Even TCP syslog can be lost if the receiving
host is unreachable. Place a syslog application (e.g. syslog-ng) on the network to receive the
syslog feeds and configure the application to write the data out to files. Ideally, have the files be
application-specific (e.g. firewall.log, router.log, maillog.log, etc.). Splunk can be installed as a
forwarder on the same host to read these files and forward them on. If Splunk requires a restart or
is otherwise unavailable (i.e. during an upgrade), it can pick up where it left off reading the files on
disk. Please see other recommendations for managing these files.
• Too many files. Ensure a single instance of Splunk does not monitor more than a few hundred
active files. If there are more than this, consider implementing a process (i.e. cron) to move the
previous day's (or week perhaps) syslog directory out of the monitored directory-structure to an
archive location. You know you have a problem with too many files if the Splunk instance
involved has something like this in its logs: File descriptor cache is full. You might also benefit
here by increasing the ulimit (see Adjust ulimit in this document).
• Avoid overwriting or hard-coding the "source" field in the data. Doing so can make
troubleshooting problematic inputs more difficult.
Syslog Input
• Strip priority out of TCP inputs. In accordance with RFC3164 a Syslog priority message is
prepended to each syslog event. By default, Splunk will strip this out on incoming UDP see
inputs.conf documentation regarding the no_priority_stripping directive. The problem is, that
many devices still prepend this priority when sending events via TCP. Splunk expects the events
to be RFC-compliant and not contain the priority so does not know to remove it. Here is an
example of what an event looks like:
<30>Sep 29 09:41:51 192.168.250.7 named[19706]...

• To strip this out, add the following to the appropriate stanza of the props.conf for the target
sourcetype:
SEDCMD-pristrip=s/^<[0-9]+>//
• Watch out for chained syslog time stamps. If an event is relayed through multiple syslog servers
(for example the local syslog on a Linux system sending events to a remote syslog server), there
may be two time stamps at the start of the event. Carefully configure your Splunk props.conf to
ensure the correct time stamp is extracted for the event.
High Performance Syslog
The Linux UDP input buffer has a fixed amount of memory allocated to it. When the amount of incoming
data exceeds this buffer, packets are dropped. On a very busy server, this could happen frequently or in
some cases continually.
The memory allocated to the UDP input buffer is distribution-specific. This means, that depending on your
flavor/version of Linux, this buffer size can vary. Be sure to understand what it is, and how it operates.
Syslog systems should be tested and tuned to perform as needed.
• Information: Calculate Capacity by Messages
• Imagine a device that generates messages that are 250-450 bytes with most being over
350.
• If we average conservatively that the messages are 400 bytes big, how many EPS could
be processed before saturating half the link such as in the Syslog-NG Example below
• A 100/mbs link is capable of 100000000/8=12500000 bytes/sec
• Half of this is 6250000 (what the Syslog-ng folks could do)
• Divide this by 400 (average bytes/message) and you get 15625 which is the total amount
of messages we could possibly receive if optimally configured with tcp given the
parameters.
• Syslog-NG Example
• The syslog-ng developers have a blog where they discuss possible volumes with
the 2.0 OSE:
• 100mbs net
• TCP messages
• 44000 messages/sec all 150 bytes long
• This means they are processing 44000*150=6600000 bytes per second
• Multiply 6600000*8 to get bandwidth: 52,800,000
• So syslog-ng optimally configured (by its developer) can use about half of the
100/mbs Ethernet connection without dropping packets
• Information: Calculate Capacity by License Size
• Imagine a 50GB license
• Divide by seconds per day 86400 to see an average of how much data could be pushed
through the network on average:
• 50000000000/86400=578703 (bytes/second)
• Multiply the above by 8 to get bits per bytes
• (50000000000/86400)*8=4629624 (bits/second)
Application or Data Specific
• SEP Data import. For Symantec Endpoint Protection, you can put the SEP server in a
configuration where it will write out temp files that a Splunk Universal Forwarder can read. Here
is the Symantec knowledge-base document on how to configure this. While it is possible to
configure SEP to send data via syslog, in some cases this data is incomplete, and unreliable. Also
be aware that there are significant differences in the event format of SEP events between versions
(most notably versions 11 and 12), which may result in failed extraction of fields if your TA or
current extractions are expecting a different version.
• Avoid reading Windows raw EVT(X) files if at all possible. Instead, configure a Splunk
Forwarder to access Windows Event Manager directly to ingest Windows Events.

• If your use case requires direct reads of the Windows EVT(X) binary files then consider
the following information:
• EVT(X) files are the raw binary-format files that Windows uses to store its logs
on the file-system. These files are nothing like normal log files and therefore
present some challenges to any attempt to reconstitute them back into usable logs
(Note: These issues have nothing to do with Splunk):
• They reference GUID/SIDs in lieu of system/user names. This means that the
“EVT(X) File Parsing Host” must have access to make AD queries to the
Domain Controllers that can provide details and convert the codes referenced by
the “Logging Host.”
• They reference DLL files that contain the pertinent information instead of
placing it in the actual log. This means any DLL referenced by the “Logging
Host” MUST be available on the “EVT(X) File Parsing Host” in order to
interpret the logs.
• Since the EVT(X) files are a subset of the information they represent, a 99MB
EVTX file converts to almost 500MB of indexed data. There are TB of logs
stored on the CIFS share. The volume both to the Splunk license, system storage,
and AD/DC calls should be considered before fully-integrating this.
• Ingest time is slow since many AD calls are necessary for GUID/SID queries.
• In our tests, many GUIDs and some DLL references didn't convert in the event
logs, leaving lots of useless events. This may be a result of either inconsistent
AD details or missing DLLs on the “Log Parsing Host”
• Splunk on Windows can natively ingest EVT(X) files
• Splunk Enterprise Security
• Implementation
• Adjust VM Swap. Lower the vm.swappiness in 'sysctl' to something like:
'vm.swappiness=10'
• Adjust ulimit. Adjust the ulimit if necessary such as:
# /etc/pam.d/su
session required pam_limits.so
# /etc/pam.d/sudo
session required pam_limits.so
# Query file descriptor settings
cat /proc/sys/fs/file-max
sysctl -a | grep fs.file-max
# Query open file descriptors
cat /proc/sys/fs/file-nr
# Configure System limits in /etc/sysctl.conf
fs.file-max = 8192
#/etc/security/limits.conf
root soft nofile 10240
root hard nofile 20240
#
splunk soft nofile 10240
splunk hard nofile 20240
• Apply changes to sysctl with “sysctl -p”
• Administration
• Manage Assets Lists. Continue to manage your ES Asset List to always get the
most value out of your deployment.
• Manage Identities. Manage your ES Identities to always get the most value out
of your deployment.

Forwarder Deployment
Change the admin password on forwarders. All Splunk systems have a default username of admin and
password of changeme and this includes Forwarders (Universal Forwarders and Full Forwarders).
• Take time to Plan your deployment prior to implementation to ensure the most success.
• Centrally-manage Splunk configurations. Ensure you have a way to consistently and accurately
manage configurations across the enterprise, such as with the Splunk deployment server
• Information: Topologies for Deployment Server
• Information: Create Server Classes
• Information: Configure Deployment Clients
• Information: Deploy Deployment Apps
• Information: Deployment Example
Windows Deployment
• Information: Custom EventLogs on Splunk for Windows are discussed here.
• Information: Splunk has the ability to use WMI to monitor Eventlogs remotely. WMI is very
clunky, and generally should not be used due to network and system performance implications.
• Before activating Splunk Windows Forwarders configure custom indexes
• Information: Monitor files and directories
• Scripted deployment for Windows UFs. You can script your deployment of Universal Forwarders
for Windows depending on what tools you have available at your disposal. There are a few things
to keep in mind though such as:
• On a version with UAC (User Access Controls) such as Visa, 2008 or Windows 7, you
must be in an admin shell to install software
• Although it is much easier to have the Splunk MSI files in a UNC that you can
mount/reach from any system, sometimes windows security policy prevents this from
working. If msiexec is failing consider copying the MSI installer local and try it again.
• There are a few things to keep in mind though, specifically that you want to pass the
following msiexec arguments: AGREETOLICENSE, INSTALLDIR (since many sites
want to install to some drive besides c
• Below is an example content that you can put in a script/package-management and it is
based on having a Splunk deployment server in place
msiexec /i systemsharepathsplunkforwarder-6.1*
DEPLOYMENT_SERVER="DS-host_or_IP:8089"
AGREETOLICENSE=Yes INSTALLDIR="c:Program
FilesSplunkUniversalForwarder" MIGRATESPLUNK=1 quiet
Linux Deployment
• Scripted deployment for Linux UFs. You can script your deployment of Universal Forwards for
Linux depending on what tools you have available at your disposal.
• There are a few things to keep in mind though, specifically that you probably want to pass
the following Splunk start-time arguments: --accept-license, --answer-yes, --no-prompt
• Below is an example content that you can put in a script/puppet/rpm and it is based on
having a Splunk deployment server in place. Note: that this hard-codes a downloads of
the Splunk UF RPM at each invocation. It would be much smarter to use a local repo and
replace that portion of the script with a call to this location with something simple like:
yum install splunkforwarder
uname -a
echo
SPLUNKHOME="/opt/splunkforwarder"
wget -O splunkforwarder-4.3-115073-linux-2.6-x86_64.rpm

'http://www.splunk.com/index.php/download_track?
file=4.3/universalforwarder/linux/splunkforwarder-4.3-115073-linux-2.6-
x86_64.rpm&ac=&wget=true&name=wget'
rpm -Uvh ./splunkforwarder-4.3-115073-linux-2.6-x86_64.rpm;
echo -e '[target-broker:deploymentServer]ntargetUri =
SPLUNK.DEPLOYMENT.SERVER.HOSTNAME_or_IP:8089' >
$SPLUNKHOME/etc/system/local/deploymentclient.conf;
$SPLUNKHOME/bin/splunk restart --accept-license --answer-yes --no-
prompt;
$SPLUNKHOME/bin/splunk enable boot-start;
[ -f "$SPLUNKHOME/etc/system/local/outputs.conf" ] && mv
$SPLUNKHOME/etc/system/local/outputs.conf
$SPLUNKHOME/etc/system/local/outputs.conf.remove;
[ -f "$SPLUNKHOME/etc/system/local/outputs.conf.remove" ] &&
$SPLUNKHOME/bin/splunk restart;
sleep 3
watch "ls $SPLUNKHOME/etc/apps"
echo
Performance
• Lots of things can affect Splunk performance, including: System resources, Splunk architecture,
Splunk configurations (e.g. lookups, extractions), and dashboards.
• Before attempting any performance remedies, first try and determine what may be adversely
affecting your deployment's performance.
• UI Performance Remedies
◦ Use Summary Indexing for increased reporting efficiency. As you add more data and more
users to Splunk, you will benefit from Summary Indexing.
◦ As of Splunk 5, it is also possible to use report acceleration. Not all searches qualify for
acceleration.
◦ As of Splunk 6, it is also possible to use data model acceleration. Any pivot or report
generated by that data model will complete much quicker than it would without the
acceleration, even if the data model represents a significantly large dataset.
Search Help
• Print the Splunk Cheatsheet (PDF or Manual) for users. This is a great resource for learning the
search language. The Splunk Reference Card PDF is also a great resource, and a laminated version
can be purchased from the Splunk Schwag store.
Storage and Data Management
• New Index. It is almost always appropriate to use multiple indexes and not just main/default.
Create a new index if the answer of any of the following questions is yes:
• Does the target data require separate retention controls from other data?
• Does the target data require separate access controls from other data?
• Will Splunk users wish to either search the target data by itself or search other data and
omit this target data?
• Consider moving your Splunk database (SPLUNKDB) to its own volume to ensure clean
separation of the binary/configuration structure and the data. This is not necessary, but there are
advantages in high-volume environments.

• Data retention. Implement data retention and disk usage controls explicitly and early instead of
waiting for a disk to fill. Configure retention in indexes.conf to push older data to remote volumes
such as NFS mount for data archive.
• Caution: Changes to the retention policy (indexes.conf) can be perilous and the effect is
not always immediate. Be sure you know what you are changing and have tracked
changes and the results appropriately to ensure it has the desired effect.
• DRP/BCP. Configure a Disaster Recovery and Business Continuity Plan for your Splunk
deployment. This will include implementing a backup plan.
• Consider backups for the $SPLUNK_HOME/etc on each standalone search head (non-pooled) and
the cluster node to a remote drive on a frequent interval. If an unmentionable happened, you can
copy this directory to a new Splunk instance to restore. (sample script below to put in cron.daily or
weekly)
• Backup the deployment server, the $SPLUNK_HOME/etc/system/local/serverclass.conf and the /
$SPLUNK_HOME/etc/deployment-apps directory to a remote drive is recommended to quickly
build a new deployment server. (sample script below to put in cron.daily or weekly)
#!/bin/sh
TSTAMP=`date +%Y%m%d01`
BAKBASE="/root/splunk/backup"
[ ! -d "$BAKBASE" ] && mkdir -p "$BAKBASE"
i#
cd /opt/splunk/etc
tar czpf $BAKBASE/deployment-apps.$TSTAMP.tar.gz
system/local/serverclass.conf deployment-apps
exit 0
• See the “Storage Hardware” section in this document for many notes regarding hardware.
Deployment Server
• Deployment Server Selection
• The DS can be collocated with any other full Splunk instance; however, there are also
some reasons why it might need to be stand-alone.
• Since the DS requires so many active TCP sessions (at least one for each connected
client), choose a system that already has a limited number of open TCP sessions to other
systems, such as a Search Head.
• Ensure the DS server has plenty of memory.
• Consider a stand-alone system if the number of deployment-clients will exceed 300-500
• Consider one Deployment Server instance for every 2000 polls per minute.
• Create a DNS host name specific to the DS (e.g. splunk-ds.yourfoo.fqdn) and use this
name for all communication from the deployment-clients. This will make it much easier
to migrate later, if you choose to.
• Adjust the polling period on clients to make a single server scale further.
• Use the clientName directive in the deploymentclient.conf to ease whitelisting and blacklisting in
your serverclass.conf
• Only deploy configuration and parsing apps, such as Technology Addons (TA's). There is very
little value in deploying dashboard based apps, and in some cases may cause complications.
• Prepend deployed configuration apps (not TA's) with "DS-". This distinction can help
tremendously when troubleshooting problems with deployment clients.
App Development
• Ensure all (if possible) searches call saved searches or use other knowledge-items such as Macros
or Eventtypes. Containing all of these knowledge-items helps with manageability of the data
across an enterprise deployment. Managing bare searches across apps or called externally via
scripts does not scale well and can create a big problem during upgrades, migrations, and other
maintenance.

• When creating fields/eventtypes refer to the Splunk Common Information Model to ensure
forward-compatibility with Splunk and Splunkbase built-ins.
• When developing an app, ensure that any log or pid files are not stored in the app's directory. If the
app is distributed via deployment server, the files and directory structure in the app will be
replaced with those from the deployment server, which would include any log or pid files.
Analytics
• Use GetWatchList. GetWatchList is a free Splunk app on Splunk Apps (formally known as
splunkbase) that allows users to manage lookup tables on the system without requiring shell or
administrative access. These lookups can be used in various ways but the most popular method is
as watchlistsOS Configuration or Hardening
• Linux Kernel Tuning Info
• Implement a central software management system (e.g. RPM repo, Puppet, Satellite Server) to
manage packages and configurations to forwarders and other related systems. Managing Splunk
instances on these remote systems always has problems and leads to issues such as:
• Very old (out of date) versions of Splunk throughout the enterprise
• Forwarders that have not had Splunk configured properly or locked down (e.g. changing
the admin password and turning off Splunk web)
• Inconsistent configurations leading to similar systems setting different metadata on the
same type of logs.
• Architecture type. Splunk works well with both 32 and 64 bit platforms; however, there is a
considerable performance improvement for 64 bit and this should be selected (both for Hardware
and Operating System) whenever possible.
• Partitions and Volumes
• Use LVM to manage underlying file-system space. Only allocate storage space to an
LVM from a Volume Group as necessary and preserve the extra for emergencies or future
use. Make better use of LVM partitioning by creating discrete logical volumes for each
major portion of the system such as /, /var, /tmp, /opt/splunk and maybe even /splunkdata

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