LH Storage Node Test

This test auto-discovers the storage nodes on the storage cluster, and for each storage node, this test reports the current health, overall size, and the load-balancing capability of each storage node. With the help of this test, administrators can not only identify overloaded nodes, but can also predict the potential failure of the node, so that efforts can be undertaken to avert the same. In addition, the test also points administrators to the nodes that are handling more I/O requests than the rest, thus shedding light on irregularities in the distribution of I/O load across disks and prompting administrators to fine-tune the load-balancing algorithm.

Target of the test : A LeftHand SAN Node

Agent deploying the test : An external agent

Outputs of the test : One set of results for storage node on the target storage cluster.

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.

SNMPPort

The port at which the monitored target exposes its SNMP MIB; The default value 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 node. 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
  • SHA224 - Secure Hash Algorithm 224 bit
  • SHA256 - Secure Hash Algorithm 256 bit
  • SHA384 - Secure Hash Algorithm 384 bit
  • SHA512 - Secure Hash Algorithm 512 bit

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 the 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
  • 3DES - Triple Data Encryption Standard
  • AES - Advanced Encryption Standard
  • AES128 - Advanced Encryption Standard 128 bit
  • AES192 - Advanced Encryption Standard 192 bit
  • AES256 - Advanced Encryption Standard 256 bit

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.

Engine ID

This parameter appears only when v3 is selected as the SNMPVersion. Sometimes, the test may not report metrics when AES192 or AES256 is chosen as the Encryption type. To ensure that the test report metrics consistently, administrators need to set this flag to Yes. By default, this parameter is set to No.

Measurements made by the test

Measurement

 Description

Measurement Unit

Interpretation

Status

Indicates the current health of this storage node.

The values that this measure can report and the numeric values that correspond to them are listed below:

Measure Value Numeric Value
Up 1
Down 2

Note:

This measure reports the Measure Values listed in the table above to indicate the current health of this storage node. However, in the graph of this measure, the state is indicated using only the Numeric Values listed in the above table.

Storage condition

Indicates the current storage condition of this storage node.

The values that this measure can report and the numeric values that correspond to them are listed below:

Measure Value Numeric Value
NotReady 1
Unoperable 2
Overloaded 3
Ready 4

Note:

This measure reports the Measure Values listed in the table above to indicate the current storage condition of this storage node. However, in the graph of this measure, the state is indicated using only the Numeric Values listed in the above table.

Total space

Indicates the total size of this storage node.

GB

Provisioned space

Indicates the space (allocated) provisioned for this storage node.

GB

Used space

Indicates the space that was already utilized in this storage node.

GB

A low value is desired for this measure. If the value of this measure is close to the Total space measure, then, it indicates that the storage node is running out of space. Administrators should therefore, free up the space in the storage node or allocate additional resources to the storage node.

Free space

Indicates the space that is currently available for use in this storage node.

GB

A high value is desired for this measure.

Space utilization

Indicates the space utilized in this storage node.

Percent

A low value is desired for this measure.

Allocated space used

Indicates the percentage of space that is utilized from the provisioned space of this storage node.

Percent

Free space pct

Indicates the percentage of space that is available for use in this storage node.

Percent

Allocated free space

Indicates the percentage of space that is available for use from the provisioned space of this storage node.

Percent

I/O read rate

Indicates the rate at which read operations were performed on this storage node during the last measurement period.

Operations/Sec

Compare the value of this measure across storage nodes to know which node handled the maximum number of I/O read operations and which handled the least. If the gap between the two is very high, then it indicates serious irregularities in loadbalancing across storage nodes.

I/O write rate

Indicates the rate at which write operations were performed on this storage node during the last measurement period.

Operations/Sec

Compare the value of this measure across storage nodes to know which node handled the maximum number of I/O write operations and which handled the least. If the gap between the two is very high, then it indicates serious irregularities in loadbalancing across storage nodes.

Data read rate

Indicates the rate at which data was read from this storage node during the last measurement period.

MB/sec

Compare the value of these measures across storage nodes to identify the slowest node in terms of servicing read and write requests (respectively).

Data write rate

Indicates the rate at which data was written to this storage nod during the last measurement period.

MB/sec

Pending I/O operations

Indicates the I/O operations that were pending on this storage node during the last measurement period.

Operations/Sec

A consistent increase in this value indicates a potential processing bottleneck with the storage node.

Read latency

Indicates the time taken to complete the read operations from this storage node during the last measurement period.

Millisecs

Write latency

Indicates the time taken to complete the write operations on this storage node during the last measurement period.

Millisecs

I/O latency

Indicates the time taken to complete the read and write operations on this storage node during the last measurement period.

Millisecs

Ideally, this value should be low. If not, it implies that the storage node is slow.