F5 Virtual Servers Test
A virtual server is capable of performing the following:
- Distribute client requests across multiple servers to balance server load;
- Apply various behavioral settings to a specific type of traffic;
- Enable persistence for a specific type of traffic;
- Direct traffic according to user-written iRules
In addition, virtual servers can also be used in the following ways:
- Directing traffic to a load balancing pool;
- Sharing an IP address with a VLAN node;
- Forwarding traffic to a specific destination IP address;
- Increasing the speed of processing HTTP traffic;
- Increasing the speed of processing Layer 4 traffic;
- Relaying DHCP traffic
Since the virtual servers are able to manage the traffic and divert client requests to servers that are managing fewer requests, poor performance and outages can be avoided. Irregularities in load balancing can cause significant delay in request processing thus affecting the user experience with the load balancing system.To avoid this, you can configure the periodic execution of the F5 Virtual Servers test. For each virtual server configured on the traffic manager, this test continuously monitors the load on the load-balancing virtual servers and reveals how well each server processes client requests. In addition, this test detects inconsistencies in load-balancing early on and warns administrators of possible deviations proactively.
Target of the test : A Big-IP/F5 Local Traffic Manager
Agent deploying the test : An external agent
Outputs of the test : One set of results for each pool configured on a traffic manager
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 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 firewall. 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:
|
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:
|
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. |
EngineId |
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 | Description | Measurement Unit | Interpretation |
---|---|---|---|
Data transmitted |
Indicates the rate at which data is transmitted from this virtual server during the last measurement period. |
MB/Sec |
Compare the value of these measures across the virtual servers to identify the server that is experiencing the maximum traffic. |
Data received |
Indicates the rate at which data is received by this virtual server during the last measurement period. |
MB/Sec |
|
Packets transmitted |
Indicates the rate at which packets were transmitted from this virtual server during the last measurement period. |
Packets/Sec |
Compare the value of these measures across the virtual servers to identify the server that is handling maximum traffic. |
Packets received |
Indicates the rate at which packets were received by this virtual server during the last measurement period. |
Packets/Sec |
|
Active connections |
Indicates the number of connections that are currently active on this virtual server. |
Number |
This measure is a good indicator of the load on the virtual server. |
Total connections |
Indicates the total number of connections established on this virtual server since the restart of the traffic manager. |
Number |
|
Connection during the last measure period |
Indicates the rate at which connections were established during the last measurement period. |
Conns/Sec |
|
Connection usage |
Indicates the percentage of connections that were used by this virtual server. |
Percent |
A value close to 100% indicates that the virtual server is currently overloaded. |
Maximum connections established |
Indicates the maximum number of connections that were established on this virtual server since the start of the traffic manager. |
Number |
|
Requests |
Indicates the rate at which requests were processed by this virtual server. |
Requests/sec |
|
CPU usage |
Indicates the percentage of time this virtual server was busy during the past minute. |
Percent |
A value close to 100 is a cause of concern. |
Average time for all connections |
Indicates the average time required for establishing all the connections to this virtual server. |
Milliseconds |
A sudden/gradual increase in the value of this measure may indicate connection issues to the virtual server. |