eG Monitoring
 

Measures reported by CtxXcXDSiteTest

A broker site is a top-level, logical representation of the XenDesktop site, from the perspective of the brokering services running within the site. It defines various site-wide default attributes used by the brokering services. A XenDesktop installation has only a single broker site instance.

This test promptly alerts administrators to the following anomalies related to the monitored site:

  • The sudden non-availability of the license server in the site;
  • Poor responsiveness of the license server;
  • Are the active sessions, desktop sessions and application sessions adequate?;
  • Are there any brokers that are currently inactive in this site?

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Lic_server_avail Indicates the availability of the license server in this site. Percent If the license server is available, a value of 100 is shown and if the license server is not available, a value of 0 is shown.

Since the license server is responsible for managing the licenses for all the components of XenDesktop, the non-availability of the license server, should have serious repercussions on the performance of the XenDesktop site. However, such adversities are averted by the 90-day grace period that XenDesktop embeds; this allows the system to function normally for 90 days if the license server becomes unavailable.

Moreover, if this measure reports that the license server is unavailable, then you may instantly want to know which license server the XenDesktop is communicating with. At this juncture, you can use the detailed diagnosis of this measure (if enabled) to ascertain the name of the license server and the port at which it listens.
Response_time Indicates the time taken by the broker to establish a connection with the license server. Secs Ideally, the response time should be low.
Total_active_sessions Indicates the total number of sessions that are currently active on this site. Number This measure is a good indicator of the load on this site.
Is_dns_res_enabled Indicates whether the DNS resolution is enabled or not on this site. Trans/Sec The values and their corresponding numeric values that this measure could report are:

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports the values Yes or No while indicating whether DNS resolution is enabled or not on this site. However, the graph of this measure will be represented using the corresponding numeric equivalents of 0 and 1 only.
Is_secure_ica_req Indicates whether/not a secure ICA is required for this site.   By default, client-server communications are obfuscated at a basic level through the SecureICA feature, which can be used to encrypt the ICA protocol.

Plug-ins use the ICA protocol to encode user input (keystrokes and mouse clicks) and address it to a server farm for processing. Server farms use the ICA protocol to format application output (display and audio) and return it to the client device.

You can increase the level of encryption for the ICA protocol when you publish a resource or after you publish a resource.

In addition to situations when you want to protect against internal security threats, such as eavesdropping, you may want to use ICA encryption in the following situations:

  • You need to secure communications from devices that use Microsoft DOS or run on Win16 systems
  • You have older devices running plug-in software that cannot be upgraded to use SSL
  • As an alternative to SSL/TLS encryption, when there is no risk of a “man-in-the-middle” attack
The values and their corresponding numeric values that this measure could report are:

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports the values Yes or No while indicating whether a secure ICA is required for this site or not. However, the graph of this measure will be represented using the corresponding numeric equivalents of 0 and 1 only.
Is_trust_req_sent_to_xml Indicates whether/not trust requests were sent to the XML service.   Trusting requests sent to the XML Service means:

  • Smooth Roaming works when connecting with the Web Interface using pass-through or smart card authentication, and when connecting with the online plug-in using smart card authentication or the Kerberos pass-through option.
  • For example, you can use workspace control to assist health-care workers in a hospital using smart cards, who need to move quickly among workstations and be able to pick up where they left off in published applications.
  • XenApp can use the information passed on from Access Gateway (Version 4.0 or later) to control application access and session policies. This information includes Access Gateway filters that can be used to control access to published applications and to set XenApp session policies. If you do not trust requests sent to the XML Service, this additional information is ignored.
The values and their corresponding numeric values that this measure could report are:

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports the values Yes or No while indicating whether/not trust requests were sent to the XML service. However, the graph of this measure will be represented using the corresponding numeric equivalents of 0 and 1 only.
Total_brokers Indicates the total number of brokers that are configured for this site. Number  
conn_lease_enabled Indicates whether/not connection leasing is enabled for this site.   Trusting requests sent to the XML Service means:

To ensure that the Site database is always available, Citrix recommends starting with a fault-tolerant SQL Server deployment by following high availability best practices from Microsoft. However, network issues and interruptions may prevent Delivery Controllers from accessing the database, resulting in users not being able to connect to their applications or desktop. The connection leasing feature supplements the SQL Server high availability best practices by enabling users to connect and reconnect to their most recently used applications and desktops, even when the Site database is not available. Although users may have a large number of published resources available, they often use only a few of them regularly. When you enable connection leasing, each Controller caches user connections to those recently used applications and desktops during normal operations (when the database is available).

The leases generated on each Controller are uploaded to the Site database for periodic synchronization to other Controllers on the Site. In addition to leases, each Controller’s cache holds application, desktop, icon, and worker information. The lease and related information is stored on each Controller’s local disk. If the database becomes unavailable, the Controller enters leased connection mode and “replays” the cached operations when a user attempts to connect or reconnect to a recently used application or desktop from StoreFront.

Connections are cached for a lease period of two weeks. So, if the database becomes unavailable, the desktops and applications that the user launched in the previous two weeks remain accessible to that user through StoreFront. However, desktops and applications that have not been launched during the previous two-week lease period are not accessible when the database is unavailable.

Connection leasing is enabled by default You can turn connection leasing off or on from the PowerShell SDK or the Windows registry.

This measure reports the value Yes if connection leasing is enabled for a site and the value No if connection leasing is not enabled for a site.

The numeric values that correspond to these measure values are as follows:

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports the values Yes or No while indicating whether/not connection leasing is enabled for the site. However, in the graph of this measure, the same will be represented using the corresponding numeric equivalents of 0 and 1 only.
license_grace_period_active Indicates whether/not the license for this site is in the grace period.   In previous versions of XenApp and XenDesktop, if the correct licenses are not installed, users will get session rejections via the license policy engine. To avoid this limitation, Citrix introduced a new concept called Supplemental Grace Period (SGP) in XenApp/XenDesktop 7.6. During the SGP, the license policy engine will grant unlimited connections, for about 15 days to allow for fixing the issue. An alarm is activated when the grace period expires, and the Delivery Controller can not checkout licenses to launch sessions from license server. After the expiration of SGP, regular license limits are enforced.

If the license for the site is in the grace period, then the value of this measure will be Yes. If the license has not entered the grace period, then the value of this measure will be No.

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports the values Yes or No while indicating whether/not the site license is in the grace period. However, in the graph of this measure, the same will be represented using the corresponding numeric equivalents of 0 and 1 only.
license_outOfBox_grace_period Indicates whether/not the license grace period for this site has expired.   If the license for the site has lived out its grace period, then the value of this measure will be Yes. If the license grace period has not expired, then the value of this measure will be No.

The numeric values that correspond to these measure values are as follows:

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports the values Yes or No while indicating whether/not the grace period of the site license has expired. However, in the graph of this measure, the same will be represented using the corresponding numeric equivalents of 0 and 1 only.
license_grace_hours_left Indicates how much time (in hours) is left for the grace period to expire. Hours This measure will report a value only if the value of the ‘license_grace_period_active’ measure is ‘Yes’.

If the value of this measure is low, then you may want to quickly install additional licenses on the site to ensure that your users receive uninterrupted access to their critical applications and desktops. Because, upon the expiry of the grace period, the Delivery Controllers in the site can not checkout licenses to launch sessions from license server.