Citrix Web Devices Test

One of the most important tasks of an administrator is to ensure that their business-critical web applications are not impacted by any slowness or network resource contention on the NetScaler appliance managing those applications. For that purpose, administrators should periodically monitor the load on the appliance, measure its bandwidth usage, and determine whether the appliance has adequate bandwidth resources to service its load. Additionally, the administrators should also keep an eye out for latencies in NetScaler operations, so that they can proactively detect potential processing bottlenecks on the appliance and avert it. To achieve this, administrators can use the Citrix Web Devices test.

This test monitors the bandwidth usage of the NetScaler appliance and alerts administrators to bandwidth contentions. Alongside resource usage, the test also tracks the requests to the appliance, so administrators can figure out if the appliance is configured with sufficient bandwidth resources to process the requests. Moreover, the test also captures and reports latencies experienced by the NetScaler appliance when processing the requests, thus bringing to light current/potential processing bottlenecks.

Target of the test : An AppFlow-enabled NetScaler Appliance

Agent deploying the test : A remote agent

Outputs of the test : One set of results for the NetScaler appliance being monitored

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed. It is recommended that you set the test period to 5 minutes. This is because, the eG AppFlow Collector is capable of capturing and aggregating AppFlow data related to the last 5 minutes only.

Host

The host for which the test is to be configured.

Cluster IPs

This parameter applies only if the NetScaler appliance being monitored is part of a NetScaler cluster. In this case, configure this parameter with a comma-separated list of IP addresses of all other nodes in that cluster.

If the monitored NetScaler appliance is down/unreachable, then the eG AppFlow Collector uses the Cluster IPs configuration to figure out which other node in the cluster it should connect to for pulling AppFlow statistics. Typically, the collector attempts to connect to every IP address that is configured against Cluster IPs, in the same sequence in which they are specified. Metrics are pulled from the first cluster node that the collector successfully establishes a connection with.

Enable Logs

This flag is set to No by default. This means that, by default, the eG agent does not create AppFlow logs. You can set this flag to Yes to enable AppFlow logging. If this is done, then the eG agent automatically writes the raw AppFlow records it reads from the collector into individual CSV files. These CSV files are stored in the <EG_AGENT_INSTALL_DIR>\NetFlow\data\<IP_of_Monitored_NetScaler>\webappflow\actual_csv folder on the eG agent host. These CSV files provide administrators with granular insights into the web appflows, thereby enabling effective troubleshooting.

Note:

By default, the eG agent creates a maximum of 10 CSV files in the actual_csv folder. Beyond this point, the older CSV files will be automatically deleted by the eG agent to accommodate new files with current data. Likewise, a single CSV file can by default contain a maximum of 99999 records only. If the records to be written exceed this default value, then the eG agent automatically creates another CSV file to write the data.

If required, you can overwrite these default settings. For this, do the following:

  1. Login to the eG agent host.
  2. Edit the Netflow.Properties file in the <EG_AGENT_INSTALL_DIR>\NetFlow\config directory.
  3. In the file, look for the parameter, csv_file_retention_count.
  4. This is the parameter that governs the maximum number of CSV files that can be created in the auto_csv folder. By default, this parameter is set to 10. If you want to retain more number of CSV files at any given point in time, you can increase the value of this parameter. If you want to retain only a few CSV files, then decrease the value of this parameter.
  5. Next, look for the parameter, csv_max_flow_record_per_file.
  6. This is the parameter that governs the number of flow records that can be written to a single CSV. By default, this parameter is set to 99999. If you want a single file to accommodate more records, so that the creation of new CSVs is delayed, then increase the value of this parameter. On the other hand, if you want to reduce the capacity of a CSV file, so that new CSVs are quickly created, then decrease the value of this parameter.
  7. Finally, save the file.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Hits

Indicates the number of requests received by the monitored NetScaler appliance.

Number

This is a good indicator of the load on the appliance. 

Bandwidth

Indicates the total amount of data received by this appliance.

KB

An abnormally high value for this measure is indicative of excessive bandwidth usage

NetScaler avg latency

Indicates the average latency experienced by the NetScaler appliance.

Msecs

A consistent increase in the value of this measure is a cause for concern, as it indicates a probable processing bottleneck on the appliance.

NetScaler max latency

Reports the high watermark of latency on the NetScaler appliance.

Msecs