Chapter 16. Managing Networks and Traffic

Note

If an application, such as SAP, running on a VM instance is down for some reason, the VM is then not counted as part of Min Instance parameter, and the AutoScale feature initiates a scaleup action if the number of active VM instances is below the configured value. Similarly, when an application instance comes up from its earlier down state, this application instance is counted as part of the active instance count and the AutoScale process initiates a scaledown action when the active instance count breaches the Max instance value.

•Max Instance: Maximum number of active VM instances that should be assigned to a load balancing rule. This parameter defines the upper limit of active VM instances that can be assigned to a load balancing rule.

Specifying a large value for the maximum instance parameter might result in provisioning large number of VM instances, which in turn leads to a single load balancing rule exhausting the VM instances limit specified at the account or domain level.

Note

If an application, such as SAP, running on a VM instance is down for some reason, the VM is not counted as part of Max Instance parameter. So there may be scenarios where the number of VMs provisioned for a scaleup action might be more than the configured Max Instance value. Once the application instances in the VMs are up from an earlier down state, the AutoScale feature starts aligning to the configured Max Instance value.

Specify the following scale-up and scale-down policies:

•Duration: The duration, in seconds, in which the conditions that you specify for a scaleup action to be true to trigger a scaleup action. The conditions defined should hold true for the entire duration you specify for an AutoScale action to be invoked.

•Counter: The performance counters expose the state of the monitored instances. By default,

CloudPlatform offers four performance counters: Three SNMP counters and one NetScaler counter. The SNMP counters are Linux User CPU, Linux System CPU, and Linux CPU Idle. The NetScaler counter is ResponseTime. The root administrator can add additional counters into CloudPlatform by using the CloudStack API.

•Operator: The following five relational operators are supported in AutoScale feature: Greater than, Less than, Less than or equal to, Greater than or equal to, and Equal to.

•Threshold: Threshold value to be used for the counter. Once the counter defined above breaches the threshold value, the AutoScale feature initiates a scaleup or scaledown action.

•Add: Click Add to add the condition.

Additionally, if you want to configure the advanced settings, click Show advanced settings, and specify the following:

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Citrix Systems 4.2 manual Managing Networks and Traffic
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4.2 specifications

Citrix Systems, a leading provider of virtualization solutions and cloud computing technologies, released version 4.2 of its popular software, Citrix XenApp, which was previously known as Presentation Server. This version marked a significant evolution in providing users with remote access to applications and desktops, emphasizing simplicity, performance, and security.

One of the standout features of Citrix XenApp 4.2 is its improved application streaming capabilities. This technology allows applications to be delivered to users in real-time, reducing the need for extensive local installations and enhancing the user experience. With application streaming, administrators can efficiently manage applications on a central server while ensuring that users have immediate access to the necessary tools.

Another highlight of this version is the enhanced security measures put in place to protect sensitive data. Citrix XenApp 4.2 includes support for SSL encryption, providing a secure communication channel for data transmitted between the server and clients. This is particularly crucial for businesses that need to comply with strict data protection regulations. Additionally, the integration of endpoint security features ensures that unauthorized access to applications is minimized.

Performance enhancements are also a critical focus in this release. Citrix optimized the delivery of applications over various network conditions, ensuring that users experience minimal latency regardless of their location. This was achieved through the incorporation of SmartAccess and SmartControl technologies, which allow administrators to set policies based on user roles, device types, and network conditions. This level of granularity enables organization-wide security without compromising on usability.

The user experience was further improved with a revamped interface, making it easier for end-users to access their applications and data. Simplified menus, clear navigation paths, and the ability to customize user settings contributed to a more efficient workflow, allowing users to focus on their tasks rather than struggling with the software.

Finally, Citrix XenApp 4.2 was designed to be highly scalable. Organizations of all sizes could deploy this solution to deliver applications efficiently, adapting to their specific needs as their user base grows or changes. This flexibility is crucial for businesses looking to future-proof their IT investments while maintaining optimal performance.

In summary, Citrix XenApp 4.2 stands out with its enhanced application streaming, robust security features, improved performance under varying conditions, user-friendly interface, and scalability, making it an ideal choice for organizations seeking to leverage virtualization for remote access to applications and desktops.
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