Entries by Ingmar Verheij

WinPE: Restarting DHCP client service

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A bare-metal deployment is build using Altiris Deployment Solutions (HP Rapid Deployment Pack, to be precise). When a client boots Windows PE 2.1 to execute a job (installation of operating system) it doesn’t seem to get an IP address from the DHCP server (Restarting DHCP client service: retry x). This is strange since the WinPE […]

Average : Mean versus Median

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The average of a set of numbers is a commonly used, but the defintion of average is poorly understood and can raise the risk of being manipulated. The average of a set of numbers can be determined with the mean or the median. To better understand the difference between mean and median I will explain […]

HP Proliant DL380G6 unexpected reboot

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Citrix XenServer 5.5.0 is installed on a HP Proliant DL380 G6 server. The customer complained that VM’s experienced unexpected shutdowns without finding the cause of the problem. After spending some time troubleshooting on the virtual machines I couldn’t find the source of the problem. No BSOD on the VM’s, UPS showed no loss of power […]

The impact of Silverlight on a virtual desktop

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A customer has a (virtualized) Citrix XenApp farm scaled for 1500 concurrent users. The environment is based on Windows Server 2003 Standard with Citrix XenApp 5 (migration to XenApp 6.x is scheduled). A business critital web-application is re-developped and requires Microsoft Silverlight. Before implementing Silverlight the impact should be determined. A big concern is a […]

"true" client side testing best practices

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When performing a LoadTest user actions are simulated. This implicates that mouse or keyboard actions are executed based on a script, based on a scenario, and that the script waits for a response on the screen. The response on the screen can be determined using API’s giving information about windows present, or the controls on […]

Business Objects (Oracle) returns wrong day of week

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Business Objects (BO) is used to generate a report showing the schedule of employees. In the schedule the day of week is displayed as a header, which makes it easy for the employees to read. The data is retrieved from an Oracle database server. There are two situations, one with a native Oracle installation and […]

FlexPlan (Filemaker Pro) stops with error 0x06d007e after XenApp 5 HRP6

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After upgrading a Citrix XenApp 5 farm with Hotfix Rollup Pack 6 (HRP6) and Internet Explorer 6 to Internet Explorer 8, the FlexPlan application (which uses Filemaker Pro) was unusable. The application is virtualized using Microsoft App-V, so the system administrators had some difficulties troubleshooting the application. Users launching the application saw the App-V progressbar […]

Loadtesting best practices – Part 2

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This is the second part in a series two about loadtesting best practices. The first part focused on the “basics” of loadtesting, most of them where about preparation. You can find the first part here. In this second part I’ll focus on some more advanced topics which are usefull in a later stage of the […]

SCOM : Configure notification for distributed applications

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Events generated by System Center Operations Manager (SCOM), like alerts and warnings, usually indicate (upcoming) problems. Notifiying you’re system administrators enables you to troubleshoot te problem as quickly as possible. For a customer I’ve configured multiple distributed applications. Each distributed application defines a critical application that needs to be monitored. All distributed applications are displayed […]

Loadtesting best practices – Part 1

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Before I start discussing best practices about loadtesting, let me first tell you what my definition of a loadtest is. “Testing a system with representative load, to determine if the nominal load can be handled”.   This means that if you start loadtesting you need to know the nominal load and have an expectation of […]