Oracle ZFS L2ARC Accesses Test

The L2ARC is the Second Level Adaptive Replacement Cache and is an SSD based cache that is accessed before reading from the much slower pool disks. The L2ARC is currently intended for random read workloads. This test monitors the accesses to the L2ARC cache and helps to understand how well the current workload is caching in L2ARC.

Target of the test : Oracle ZFS Storage System

Agent deploying the test : A remote agent

Outputs of the test : One set of results for the Oracle ZFS Storage System being monitored.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed.

Host

The IP address of the target system that is being monitored.

Port

The port number through which Oracle ZFS Storage System communicates. The default port is 215.

User, Password and Confirm Password

By default, this test uses the REST API commands to pull out the required metrics. To execute the REST API commands, the eG agent requires the permission of a local administrator user who has been assigned with Basic role and a custom role with Analytics authorization and read permission. Specify the credentials of such a user in the USERNAME and PASSWORD text boxes and confirm the Password by retyping it in the CONFIRM PASSWORD text box. To create a new user with the required permissions, refer Creating a new user on Oracle ZFS Storage System.

Timeout

Specify the time duration for which this test should wait for a response from the storage system in the TIMEOUT text box. By default, this is 60 seconds.

Num DD Messages

By default, the NUM DD MESSAGES parameter is set to 10. This means that, by default, the detailed diagnosis of this test will report the details of the top-10 records of the measures that are obtained upon execution of this test. To view the details of more records as part of detailed metrics, you will have to increase the value of this parameter. Likewise, to view the details of less than 10 records, reduce the value of this parameter.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD frequency.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Peak hits

Indicates the peak hits during the last measurement period.

Hits/sec

The detailed diagnosis shows when performance of the device had hit peaks.

Average hits

Indicates the average hits during the last measurement period.

Hits/sec

A high value is desired for this measure. A very low value is a cause for concern.

Peak misses

Indicates the peak misses during the last measurement period.

Misses/sec

The detailed diagnosis shows when the performance of the device had failed.

Average misses

Indicates the average misses during the last measurement period.

Misses/sec

A high value of this measure can cause performance degradation of the system and increases latency.