Closing The Application Performance Visibility Gap Inherent To Citrix Environments

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Adele Hudson
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WHITE PAPER: COMPUWARE APM FOR CITRIX XenApp/ XenDesktop Closing The Application Performance Visibility Gap Inherent To Citrix Environments Many companies have invested in Citrix XenApp and

The benefits of desktop virtualization have resulted in widespread adoption of Citrix.

This paper will discuss this complexity and the challenges, and what is needed to successfully deploy these environments for best end-user experience.

Businesses have many valid reasons to adopt this technology as it offers: More effective management.

1 WHITE PAPER: COMPUWARE APM FOR CITRIX XenApp/ XenDesktop Closing The Application Performance Visibility Gap Inherent To Citrix Environments Many companies have invested in Citrix XenApp and XenDesktop environments to enable their internal users, employees, partners or customers to connect to their corporate applications from any device. The benefits of desktop virtualization have resulted in widespread adoption of Citrix. However, as with most technology shifts, virtualization can be complex and has its own set of challenges in optimizing Citrix to improve performance of back-end business applications. This paper will discuss this complexity and the challenges, and what is needed to successfully deploy these environments for best end-user experience. INTRODUCTION Many companies have invested in Citrix XenApp and XenDesktop, to allow their internal users, employees, partners or customers to connect to their corporate applications from any device. Businesses have many valid reasons to adopt this technology as it offers: More effective management. Citrix helps reduce the cost of deploying and managing applications on end-user desktops with central management from the Citrix server. Device independence: Today, bringing your own device is a reality and, having a client that can run on multiple clients OSs is a big advantage. Citrix provides the technology that enables mobile devices. It also fits in as part of a Virtual Desktop or VDI strategy. Network cost reduction: Citrix technology and the ICA protocol have been designed to use less bandwidth than other applications as it only contains the screen information, not the total payload data. When application performance issues arise (as they always do), Citrix can be mistakenly blamed as the cause of poor performance when the real issues exist elsewhere. Some common questions encountered following a Citrix deployment include: How to measure the load on the Citrix environment? How many Citrix users can one Citrix server support? Is the network bandwidth sufficient to service all the users and back-end applications? What about visibility into application usage when transactions compete for bandwidth? Visibility into the users and who is using what application? How to quickly assess the quality of service received by the users? Are there performance issues when the service is delivered through Citrix? When users complain, how fast can the issue be found? Is it the network, the Citrix environment, the back-end application or the database that is at fault? There is a performance visibility gap with deskop virtualization that can be a challenge in a 24/7 operations environment where service degradation or business application downtime is just not acceptable. And the difficulty comes from the way the service is delivered to end users through Citrix. What is a Citrix environment? A Citrix environment is comprised of three base components: 1.) The Citrix Client connects to the Citrix server farm over the network, using the ICA protocol. The ICA protocol typically sends information about screen updates to the client and allows the client to communicate mouse movements and keyboard entries back to the server. To do that it uses separate channels. 2.) Several clients can connect to a Citrix server on the Citrix farm. The server will generate an active user session for each connected user. Within that user session, the end users can interact with different applications (browsers, fat clients, etc.) using the Citrix thin client terminal or a full desktop computer that acts as a Citrix terminal. 3.) The Citrix farm is connected to the back-end applications that will receive the requests from the Citrix farm on behalf of end users. Typical Citrix Infrastructure

The Challenges The utilization of a Citrix environment introduces what we call a performance visibility gap that prevents IT from being able to track and understand the end-to-end user transactions

And this is the lack of visibility into the end-user experience which brings new challenges.

2 The Challenges The utilization of a Citrix environment introduces what we call a performance visibility gap that prevents IT from being able to track and understand the end-to-end user transactions from the user s click from a device, all the way into the back-end application and back. From an IT perspective, all the traffic from the Citrix pipe is indistinguishable. And this is the lack of visibility into the end-user experience which brings new challenges. They can be divided into four categories: Therefore it is important to monitor the network connection between the Citrix client and the Citrix server in order to quickly identify possible network bottlenecks because they can affect the end-user experience. 1.) Limited insight into capacity and load 2.) Reduced visibility into end-user experience 3.) No correlation between the Citrix user session and the back-end application transaction 4.) No end-to-end transaction monitoring So how can these challenges be identified and addressed? Limited Insight into Capacity and Load A great use for Citrix is to help reduce bandwidth and enable applications overcome WAN challenges. For instance, the client application can be hosted on the Citrix server so that only mouse, screen updates and information such as printing have to travel to the Citrix client, reducing the necessary network traffic. In general, the screen size and/or the number of screen updates affect the bandwidth consumption of a Citrix session. Citrix provides some guidance to help understand the impact on network bandwidth consumption. Identification of the Bandwidth Consumption by Client Locations Compuware APM monitors performance of each network session between end users in remote locations and the data center where Citrix servers reside. These performance measurements reflect all key aspects of network connectivity required for smooth delivery of applications over Citrix: network round-trip time and retransmissions rate effective network throughput experienced by end users network bandwidth usage per location, with per-application breakdown (link utilization statistics can also be gathered using NetFlow) TCP connectivity availability from client to server The table below shows how bandwidth consumption of the ICA protocol depends on the type of application being used. The bandwidth can range between 53 kbps to 1,8 Mbps per session. Average Bandwidth per Session for XenDesktop For more information: download/ /xendesktop%20to%20branch%20 Offices_v2.pdf This is the reason why it is important to quickly identify and differentiate what traffic goes through the Citrix pipe also known as the ICA channels. The ICA channels identify what application (SAP, printing, audio, etc.) uses what chunk of the bandwidth. How does that help? As an example, it may be important to understand how many people are actually printing through Citrix, as this can have a significant impact on the bandwidth consumption and the average user load of the system as seen below. Graphs Showing Critical Information like Total Loss Rate, End-To-End RTT and Realized Bandwidth 2

The screen capture shows a network situation for a Citrix environment with high loss rates and shaky Round Trip Times (RTT) resulting in a negative impact on the actual bandwidth.

Monitoring the load on the Citrix servers and the relationship between active sessions and open sessions on one Citrix server is needed to gather this kind of insight.

additional hundred servers. Citrix (communication between a Citrix farm and back-end applications) is visible, it can t be correlated to a specific location or an identified user.

The traffic between the Citrix servers to the applications can be analyzed in real time. This analysis provides insight on the level or performance the identified end users are really getting.

3 The screen capture shows a network situation for a Citrix environment with high loss rates and shaky Round Trip Times (RTT) resulting in a negative impact on the actual bandwidth. This directly impacts the user experience. One typical question from Citrix administrators is: How many user sessions can we have on one Citrix server? Monitoring the load on the Citrix servers and the relationship between active sessions and open sessions on one Citrix server is needed to gather this kind of insight. For an organization implementing a new Citrix deployment for a pool of 6,000 users, where every single Citrix server can serve only 15 to 20 users, this makes a huge difference and would require an additional hundred servers. Citrix (communication between a Citrix farm and back-end applications) is visible, it can t be correlated to a specific location or an identified user. This is an example of where an application performance management solution can get back this visibility into the actual experience of the users. The traffic between the Citrix servers to the applications can be analyzed in real time. This analysis provides insight on the level or performance the identified end users are really getting. This is a key aspect for any application rollout over a Citrix environment to monitor and understand how the business application adoption rate evolves and whether or not the users are satisfied. Who is actually using the new application through Citrix and who still uses the soon-to-be-retired app? Or what applications are users using on a Citrix environment? Network Utilization by Application Capacity Planning Graphs Showing the Load on the Two Citrix Farms That is why it is important to gather the information on the number of sessions, the CPU, memory and disk utilization of the server. This provides more insight into the usage and capacity of the different servers within the Citrix farm. The screen shot above shows the number of sessions per server on the left and the percentages of memory, CPU and disk utilizations on the right (note that the percent scales are different between the two images). We see that on Saturday and Sunday the number of sessions drops considerably. The CPU and memory consumption are quite similar, around 20 percent for both servers. The server from the top chart is suffering from much higher disk utilization (between 20 and 60 percent) where on the server depicted on the lower chart disk utilization remains below 20 percent. This might indicate some rogue processes or possibly a hardware issue. This graphic shows an example of the different applications that are being accessed through the Citrix farm, quickly providing visibility into applications that are being used the most, based on, in this case, bandwidth consumption. Reduced Visibility into End-User Experience Another key challenge is visibility into end-user experience and the quality of service that they are getting from the back-end application. Who is using what application? How reliable and consistent is the application delivery to the location of service? How does Citrix impact the end-to-end service delivery? In most cases, Network Performance Monitoring (NPM) can be used to understand which locations were using what applications. One of the main reasons was to see if business applications were affected by other applications using the same network bandwidth and server infrastructure resources. With the Citrix protocol (ICA), information on end-user experience, once available, is no longer visible. IT is driving in the fog. The system basically behaves as a black box. The Citrix traffic only doesn t provide insight into the application performance being used. Even though the proxied application traffic going through Application Usage in Bytes for Citrix Users This can also be monitored by users to understand what applications they have been using. In this example, the graph shows when a user is using a specific application. It is clearly visible that a large portion of that traffic is actually the traffic to the Citrix server (ICA). It also gives precise information on what applications are being used by the user through Citrix. The ICA connection can be analyzed in even more detail. The performance of the network link between the end user s display and the XenApp/XenDesktop server is analyzed individually for each published application and ICA channel. 3

customers to analyze the traffic traveling from the Citrix server to the application servers.

It also measures the business impact by collecting the occurrences of application-specific errors and the number of users that may be affected.

This allows customers to understand what transactions are being used, by whom, what is the response time of those transactions, and if transactions fail, what errors occurred.

domain isolation for performance problems.

4 customers to analyze the traffic traveling from the Citrix server to the application servers. It provides all the key performance metrics you need including response time for each user identified by name, by individual transaction. It also measures the business impact by collecting the occurrences of application-specific errors and the number of users that may be affected. Support includes a large range of network protocols and application communication: web-based, SAP, Oracle E-Business, Database, MQ, SOAP, XML, CIFS, Cerner, Siebel and many more. This allows customers to understand what transactions are being used, by whom, what is the response time of those transactions, and if transactions fail, what errors occurred. Graphical Representation of ICA channels (Source: Citrix) The reports below show the traffic breakdown between interactive screen updates, audio/video media, print and USB access, enabling fault domain isolation for performance problems. Published Citrix application names are reported together with channel names, adding further precision to the fault domain isolation input data (Reports produced by Compuware s Data Center Real User Monitoring solution). Response Time of Back-end Citrix Applications The screen shot above shows the response time for the different pages that users visited. The first row contains a web transaction with a high number of slow operations (162) and a very low application performance (0.6%), indicating a problem with this specific transaction. The software identifies if and where there is a performance degradation problem and how it affects the customers and end users. For instance, it is clearly shown here that the problem is not within the Citrix environment, but with the business application itself. Being able to link the Citrix user session to the back-end application transactions is key when monitoring the quality of service received by the end user and the perceived overall user satisfaction. The question to ask is: which Citrix users are affected by performance degradation? This allows IT to understand the performance delivered to the Citrix users for the different back-end applications. The decode of the ICA protocol gives more insight into the published applications, the channels being used and the performance of the Citrix login No correlation between the Citrix user session and the back-end application transaction It is important to ensure that the Citrix environment is working properly, but even more importantly to get insight into the performance of the applications being delivered via Citrix. Compuware APM includes this passive network listening technology which allows Response Times of Back-end Transaction Executed by a Specific Citrix User 4

As a result, the transaction details shown above clearly identify the different transaction steps performed when a user logs into Citrix (LOGIN) and then accesses a XenApp application.

5 As a result, the transaction details shown above clearly identify the different transaction steps performed when a user logs into Citrix (LOGIN) and then accesses a XenApp application. Not only does this give insights into the transactions/pages the user accessed, but also which of these pages were slow on the back-end applications. As an example, it took up to 2.37 seconds to reconnect. No End-to-End Monitoring When monitoring a Citrix environment, it is important to have a solution that allows for looking at Citrix as a component within the entire application delivery chain. Furthermore, in order to be able to identify where an issue originates, it is important to understand: 1.) Was there a bandwidth issue between the Citrix server and client? Did any of the specific use cases (printing, using USB drives, etc.) have a negative influence on the bandwidth consumption? On the one hand, the front-end traffic is being analyzed based on the performance of the network and the ICA channels information. On the other hand, the back-end traffic analysis looks at understanding the performance of the application transactions (SAP, Oracle E-Business, Homegrown, Electronic Health and Medical Records [EMR\EHR], web, DB, etc.). It gives general visibility into the applications being used by the Citrix end users. The TCAM will provide the necessary information on the performance of the Citrix servers and will allow stitching the Citrix user sessions with the back-end application transaction providing end-to-end communication monitoring. In addition, robots (synthetic) can be deployed to measure the performance of critical transactions against the Citrix environment, or to assess the quality of service received from remote locations. All this information is brought together within Compuware APM to give the full end-to-end visibility. 2.) Are there any resource availability constraints or load balancing issues on the Citrix farm? 3.) Was there a problem with the back-end application itself such as SAP, Oracle E-business, the homegrown application, etc? Example of an SAP application delivered through Citrix Compuware APM for Citrix Infrastructure The above diagram shows how Compuware APM can monitor the entire application delivery chain including the Citrix infrastructure. The probe, also called the Agentless Monitoring Device or AMD, passively captures the network traffic between: The Citrix clients and the Citrix server and The Citrix server and the back-end applications. In addition, it gathers information received from the Thin Client Analysis Module (TCAM). This agent is installed on the Citrix server. The TCAM provides information on the Citrix user sessions and system resources consumed by the Citrix farm. It is important to be able to correlate the Citrix sessions (Citrix server to back-end applications) to the individual front-end user. In the meantime, monitoring the resource consumption on the Citrix server (CPU, memory, disk I/O and Citrix sessions) gives you insights into the conditions under which the server operates. Summary For many organizations, the Citrix environment is the cornerstone that delivers business-critical applications and key services to their end users. Citrix XenDesktop and XenApp are used as enablers to make the management of these applications easier, lower network costs and make it easier to use the application in today s bring your own device context. In the meantime, Citrix creates a black box effect that negatively impacts IT by eliminating the visibility into the business application end-user experience. The consequences include: No visibility into the true end-user experience from the location of service, the data center and the back-end business application, means the quality of service delivered can t be measured. No visibility into end-user experience means no easy way of assessing the business impact of a performance issue in case of performance degradation. No visibility into end-to-end transactions means longer time to detect, isolate and correct performance issues. No visibility into end-to-end transactions means more IT resources involved and more time spent on service restoration and incident calls. 5

Compuware APM fills this gap and provides deep insight into the quality of service each user receives, including: The fastest performance issue fault isolation in the industry from the click of the

support to deeply assess the true performance end users are receiving at the location of service No sampling with 100% of the Citrix user transactions captured Unique capability to correlate user

6 Compuware APM fills this gap and provides deep insight into the quality of service each user receives, including: The fastest performance issue fault isolation in the industry from the click of the end user, through Citrix, to the data center, to the back-end business application and all the way back The most detailed end-user experience The broadest coverage of business application protocols support to deeply assess the true performance end users are receiving at the location of service No sampling with 100% of the Citrix user transactions captured Unique capability to correlate user traffic on the front-end to the sessions on the back-end through Citrix The least intrusive solution and the easiest to set up: The solution is passive and agentless. Auto-discovery and recognition of users and business transactions make configuration effortless. You will easily understand: What applications are being used in the Citrix environment and by whom Which applications, locations and users are impacted by poor performance How Citrix is being used across users and applications How to optimize the use of the network bandwidth to better service the most critical applications How to optimize back-end application performance for best user satisfaction, where issues are originating and access troubleshooting information into the network, Citrix farm and back-end applications, just a click away. ABOUT COMPUWARE APM Compuware APM is the leader in a new generation of application performance management. Unlike traditional APM solutions that are heavy, difficult and reactive, Compuware APM is light, smart and proactive. Compuware APM is built to manage the complexity of today s most challenging modern applications including mobile, cloud, Big Data and SOA. Compuware APM optimizes and monitors tens of thousands of applications for more than 4,000 customers, large and small, around the globe. Through the lens of end-user experience, our customers enjoy faster performance, proactive problem resolution, accelerated time-to-market and reduced application management costs through smarter analytics, advanced APM automation and a unique performance lifecycle foundation. Compuware is recognized as a leader in the Magic Quadrant for Application Performance Monitoring report. Read more about Compuware s leadership in the APM market. To learn more about Compuware APM, please visit: compuware.com/apm Compuware Corporation, the technology performance company, makes technology make a difference by providing software, experts and best practices to ensure technology works well and delivers value. Compuware solutions make the world s most important technologies perform at their best for leading organizations worldwide, including 46 of the top 50 Fortune 500 companies and 12 of the top 20 most visited U.S. web sites. Learn more at: compuware.com. Compuware Corporation World Headquarters One Campus Martius Detroit, MI Compuware Corporation Compuware products and services listed within are trademarks or registered trademarks of Compuware Corporation. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners jg

Closing the Application Performance Visibility Gap Inherent to Citrix Environments

Closing the Application Performance Visibility Gap Inherent to Citrix Environments Table of contents Page Chapter 3 4 5 5 6 8 9 11 12 Executive summary Introduction What is a Citrix environment? The challenges