| Measurement |
Description |
Measurement Unit |
Interpretation |
| Server_state |
Indicates the current state of the virtual server bound to this service in the ADC device. |
|
The values that this measure can report and their numeric equivalents are listed in the table below:
| Measure Value |
Numeric Value |
| Up |
0 |
| Down |
1 |
| Out of service |
2 |
| Transition out of service |
3 |
| Down when going out of service |
4 |
| Unknown |
-1 |
Note: By default, this measure reports the above-mentioned Measure Values to indicate the state of the virtual server. However, the graph of this measure will be represented using the corresponding numeric equivalents i.e., 0 or 1.
The Detailed Diagnisis of this measure shows the Service Type, Primary Port and the Primary IP address of the virtual server. |
| Server_cons |
Indicates the number of current connections to the actual servers behind the virtual server bound to this service. |
Number |
These measures serve as good indicators of the current workload of a service. |
| Client_cons |
Indicates the number of current client connections to this service. |
Number |
| Active_cons |
Indicates the number of active transactions (including those in the surge queue) handled by this service. |
Number |
| Load_on_service |
Indicates the load on this service. |
Number |
ADC uses a special type of monitor known as a Load Monitor to calculate the load on each service in the network. Load calculation enables the ADC Load Balancing engine to make load balancing decisions and distribute the traffic appropriately between the services.
This measure reports the service load as calculated by the Load Monitor. By comparing the value of this measure across services, you can quickly determine whether/not the load is balanced across services, isolate the overloaded services, and initiate measures to fix the load-balancing irregularities. |
| Req_in_idle |
Indicates the number of requests in the idle queue or the reuse pool. |
Number |
Ideally, the value of this measure should be low. A very high value indicates that too many idle connections have been placed in the idle queue/reuse pool and have not been reused yet. Such requests drain resources unnecessarily. To avoid this, you can limit the number of connections that can be added to the connection reuse pool of the appliance. You can add an HTTP profile and attach it at a virtual server (VServer) or a service level. You can use this profile to limit the number of connections that can be added to the connection reuse pool. |
| Avg_tftb |
Indicates the average response Time to First Byte (TTFB)to the ADC device from the server. |
Milliseconds |
Time to First Byte is a metric used to measure response time, calculated based on the time it takes to send a GET Request and receive a GET Response back from a server. A high value is a clear indication of network congestion or connection failure. |
| Max_open_conns |
Indicates the maximum number of open connections that are allowed on this service. |
Number |
|
| Surge_queue |
Indicates the number of requests in the surge queue of this service. |
Number |
The ADC device can be used to limit the number of simultaneous requests that are passed on to a server. When a request is completed, additional requests are forwarded to the server. If a request arrives and the server is handling the maximum configured number of requests, the ADC device places the new request in a surge queue, where the request waits for its turn to be sent to the server for processing. The surge queue allows a server to run at peak capacity without the risk of having it spiral out of control because of a surge of incoming requests. If the surge queue is consistently greater than 0, this indicates that the server is not able to keep up with the workload and additional server capacity is required. On the other hand, a periodic surge is not a cause for concern.
When a surge in client requests overloads a server, server response becomes slow, and the server is unable to respond to new requests. The Surge Protection feature ensures that connections to the server occur at a rate that the server can handle. The response rate depends on how surge protection is configured. The ADC appliance also tracks the number of connections to the server, and uses that information to adjust the rate at which it opens new server connections. |
| Server_cons_in_est |
Indicates the number of connections to the virtual server bound to this service that are currently in ESTABLISHED state. |
Number |
|
| Req_data_received |
Indicates the amount of data received as requests on this service or virtual server during the last measurement period. |
MB |
|
| Res_data_received |
Indicates the amount of data received as response on this service or virtual server during the last measurement period. |
MB |
|
| Req_received |
Indicates the number of requests received on this service or virtual server during the last measurement period. |
Number |
|
| Res_received |
Indicates the number of responses received on this service or virtual server during the last measurement period. |
Number |
|
| Packets_received |
Indicates the number of packets received on this service or virtual server during the last measurement period. |
Number |
|
| Packets_sent |
Indicates the number of packets sent from this service or virtual server during the last measurement period. |
Number |
|
| Throughput |
Indicates the rate at which the data is received from and sent by this service or virtual server during the last measurement period. |
Mbps |
Comparing the throughput across services will enable you to instantly isolate the service that is consuming bandwidth excessively. |
| Service_hits |
Indicates the number of times this service has been provided during the last measurement period. |
Number |
|