Cassandra Buffer Pools Test

The Cassandra database node manages an internal buffer pool system. This buffer pool is meant to keep allocations and GC lower by recycling on and off heap buffers. If the buffer pool size is inadequate, then, the requests may not be serviced by the buffer pool more often that not. To avoid such frequent buffer pool misses, it is necessary to keep a vigil on the buffer pool of the Cassandra database node. The Cassandra Buffer Pools test helps administrators achieve this!

This test reports the size of the buffer pool and also reports the count of service requests that were not serviced by the buffer pool. Using this test, administrators can figure out how often the buffer pool failed to service requests and figure out if it is attributed to the poor sizing of the buffer pool.

Target of the test : A Cassandra Database

Agent deploying the test : An external/remote agent.

Outputs of the test : One set of results for the target Cassandra Database node that is being monitored.

Configurable parameters for the test
Parameters Description

Test Period

How often should the test be executed.

Host

The host for which the test is to be configured.

Port

The port on which the specified host listens. By default, this is 9042.

JMX Remote Port

Here, specify the port at which the JMX listens for requests from remote hosts. Ensure that you specify the same port that you configured in the cassandra-env.sh file (if the target Cassandra Database node is installed on a Unix host) or the cassandra-env.ps1 file (if the target Cassandra Database node is installed on a Windows host) in the <CASSANDRA_HOME> directory used by the target Cassandra Database node. To know how to specify the remote port, refer to Enabling JMX Support for JRE.

JMX User and JMX Password

By default, the JMX User parameter is set to none. If JMX requires authentication only (but no security), then ensure that the user and password parameters are configured with the credentials of a user with read-write access to JMX. To know how to create this user, refer to Configuring the eG Agent to Support JMX Authentication.

Confirm Password

Confirm the Password by retyping it in this text box.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Misses

Indicates the number of times requests were not serviced from the buffer pool during the last measurement period.

Number

A low value is desired for this measure.

Miss rate

Indicates the rate at which requests were not serviced from the buffer pool during the last measurement period.

Misses/sec

A high value for this measure indicates that the buffer pool needs to be allocated with additional resources.

Size

Indicates the size of the buffer pool.

MB