New Relic Infrastructure Agent¶ ↑

Gem for collecting memcached, disk, cpu and IO statistics. Collected stats are sent to the New Relic RPM application.

Use this gem to collect statistics from a given host by running newrelic_ia -a as a daemon. This will contribute System/* metrics to your RPM console which can be viewed with custom dashboards.

Synopsis¶ ↑

newrelic_ia [ options ] aspect, aspect.. 

aspect: one or more of 'iostat' or 'disk' or 'memcached' (more to come)

-a, --all                        use all available aspects
-v, --verbose                    debug output
-q, --quiet                      quiet output
-e, --environment=ENV            use ENV section in newrelic.yml
    --install                    create a default newrelic.yml
-h, --help                       Show this help message.

Requirements¶ ↑

• New Relic Agent version 2.10.6 or later

• Gold Subscription for creating and viewing custom dashboards

Install¶ ↑

sudo gem install newrelic_ia

Once installed, run from the home directory of your Rails application, or create a separate working directory and run

newrelic_ia --install

to create a template newrelic.yml file you can use. Edit this file and substitute your license key and app_name value.

specify memcached nodes in memcached-nodes.txt.

Credits¶ ↑

Special thanks to Chandra Patni and Tony Ford of IGN for the Memcached sampler.

Memcached Details¶ ↑

Memcached statistics sampler collects subset of stats provided by memcached daemon, once a minute. In addition it computes other stats dervied from memcached stats. Also support stats derivatives over time to compute rate etc. Specify Memcached nodes configuration in the newrelic.yml file.

Memcached stats are reported for each node and also sample reports aggregated stats

Stats Detail¶ ↑

uptime                     Number of seconds this server has been running
curr_items                 Current number of items stored by the server
total_items                Total number of items stored by this server 
                           ever since it started
bytes                      Current number of bytes used by this server to store items
curr_connections           Number of open connections
total_connections          Total number of connections opened since 
                           the server started running
connection_structures      Number of connection structures allocated by the server
cmd_get                    Cumulative number of retrieval requests
cmd_set                    Cumulative number of storage requests
get_hits                   Number of keys that have been requested and found present
get_misses                 Number of items that have been requested and not found
evictions                  Number of valid items removed from cache to free 
                           memory for new items
bytes_read                 Total number of bytes read by this server from network
bytes_written              Total number of bytes sent by this server to network
limit_maxbytes             Number of bytes this server is allowed to use for storage
threads                    Number of worker threads requested

Derived Stats (computed stats):

free_maxbytes              Number of free bytes this server has available for storage

Stats Derivatives (time derivatives of stats):

hit_ratio                  Percent of keys that have been requested and found present
miss_ratio                 Percent of keys that have been requested and found missing
rpm                        Requests per minutes 
gpm                        Gets per minutes
hpm                        Hits per minutes
mpm                        Misses per minutes
spm                        Sets per minutes
fpm                        Flushes per minutes
epm                        Evictions per minutes

Sample Custom View¶ ↑

Liquid template for NewRelic custom dashboard:

<div>
    <div style="float: left; width: 50%;">
        {% line_chart value:average_value title:'Cache Miss Ratio' metric:'System/Memcached/Miss Ratio' simple_tooltip:true label:segment_3 value_suffix:'%' %}
    </div>
    <div style="float: left; width: 50%;">
        {% line_chart value:average_value title:'Cache Memory' regexp:'System/Memcached/(Bytes|Free Bytes|Limit Maxbytes)' simple_tooltip:true label:segment_3 %}
    </div>
    <br style="clear: both" />
</div>

<div style="padding-top: 20px">&nbsp;</div>

<div>
    <div style="float: left; width: 50%;">
        {% line_chart value:average_value title:'Cache Gets & Sets' regexp:'System/Memcached/(Gpm|Spm)' simple_tooltip:true label:segment_3 %}
    </div>
    <div style="float: left; width: 50%;">
        {% line_chart value:average_value title:'Cache Misses, Flushes, & Evictions' regexp:'System/Memcached/(Mpm|Epm|Fpm)' simple_tooltip:true label:segment_3 %}
    </div>
    <br style="clear: both" />
</div>

<div style="padding-top: 20px">&nbsp;</div>

<div>
    <div style="float: left; width: 50%;">
    {% line_chart value:average_value title:'Active Connections' metric:'System/Memcached/Curr Connections' simple_tooltip:true hide_legend:true %}
    </div>
    <div style="float: left; width: 50%;">
    {% line_chart value:average_value title:'Cache Objects' metric:'System/Memcached/Curr Items' simple_tooltip:true hide_legend:true %}
    </div>
    <br style="clear: both" />
</div>