Nimble I/O Performance Test

This test monitors the I/O operations of the Nimble storage system and reports how well the I/O operations were read from/written to sequentially and in random. This way, administrators can analyze the throughput of the Nimble Storage system and take remedial measures before any discrepancies arise.

Target of the test : A Nimble Storage

Agent deploying the test : An external agent

Outputs of the test : One set of results for the target Nimble Storage that is to be monitored.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed.

Host

The IP address of the host for which this test is to be configured.

Port

The port at which the specified host listens. By default, this will be NULL.

SNMPPort

The port at which the monitored target exposes its SNMP MIB; the default is 161.

SNMPVersion

By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPVersion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list.

SNMPCommunity

The SNMP community name that the test uses to communicate with the storage. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVersion chosen is v3, then this parameter will not appear.

Username

This parameter appears only when v3 is selected as the SNMPVersion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. 

Context

This parameter appears only when v3 is selected as the SNMPVersion. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box.  By default, this parameter is set to none.

AuthPass

Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPVersion selected is v3.

Confirm Password

Confirm the AuthPass by retyping it here.

AuthType

This parameter too appears only if v3 is selected as the SNMPVersion. From the AuthType list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:

  • MD5 – Message Digest Algorithm
  • SHA – Secure Hash Algorithm

EncryptFlag

This flag appears only when v3 is selected as the SNMPVersion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. 

EncryptType

If this EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:

  • DES – Data Encryption Standard
  • AES – Advanced Encryption Standard

EncryptPassword

Specify the encryption password here.

Confirm Password

Confirm the encryption password by retyping it here.

Timeout

Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds.

Data Over TCP

By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Sequential read IOPS

Indicates the rate at which I/O operations were read sequentially during the last measurement period.

IOPS

 

Sequential write IOPS

Indicates the rate at which I/O operations were written sequentially during the last measurement period.

IOPS

A high value is desired for this measure. A low value for this measure may indicate a poor throughput thus resulting in a decrease in the free space and the performance of the disks.

Random read IOPS

Indicates the rate at which random I/O operations were read during the last measurement period.

IOPS

 

Random write IOPS

Indicates the rate at which random I/O operations were written during the last measurement period.

IOPS

 

Total IOPS

Indicates the total number of I/O operations performed per second.

IOPS

This measure is the total of Sequential read IOPS, Sequential write IOPS, Random read IOPS and Random write IOPS measures. The gradual increase in the value of this measure indicates a consistent rise of I/O load on the storage.

Total I/O reads

Indicates the total number of I/O operations that were read during the last measurement period.

Reads

 

Total I/O writes

Indicates the total number of I/O operations that were written during the last measurement period.

Writes

Ideally, high value is desired for this measure.

Avg. I/O read latency

Indicates the average time taken to process each read operation during the last measurement period.

MilliSeconds

Very high values for these measures are indicative of the existence of road-blocks to rapid reading/writing by the Nimble Storage.

By observing the variations in these measures over time, you can understand whether the latencies are sporadic or consistent. Consistent delays in reading/writing could indicate that there are persistent bottlenecks (if any) in the Nimble Storage to speedy I/O processing.

Avg. I/O write latency

Indicates the average time taken to process each write operation during the last measurement period.

MilliSeconds

Avg latency

Indicates the average time taken to process the total read and write operations

Milliseconds

This measure is the sum of Avg. I/O read latency and Avg. I/O write latency measures. Ideally, the value of this measure is preferred to be low. A high value of this measure indicates that the storage is taking more time to process the I/O operations.

Total IOPS

Indicates the total number of I/O operations performed per second.

IOPS

This measure is the total of Sequential read IOPS, Sequential write IOPS, Random read IOPS and Random write IOPS measures. The gradual increase in the value of this measure indicates a consistent rise of I/O load on the storage.