Performance/Sizing

This article is part of a mini-series. You can find the other articles here. As we have seen in part 1 of this series, when sizing a new farm the first thing we need to know is the capacity of the existing farm. Armed with data on capacity and additionally load, we can easily calculate the capacity of a new farm. In this article I describe how to determine capacity of the four relevant hardware components of a XenApp server: CPU, memory, storage and network.

This article is part of a mini-series. You can find the other articles here. One of the first things you need to do after starting a XenApp farm upgrade project is to answer the obvious question from management: how much will it cost? In order to be able to answer, you need to have a good understanding of the resources required. In other words, you need to size the farm.

Windows 7 comes with several features that promise to greatly improve file access over a WAN. One of them is version 2 of the SMB protocol, another transparent caching. This article describes how I measured their effectiveness.

[Update on 29/06/2012: added tests 5 and 6 with RAID controller cache and Atlantis Ilio] When a 400 GB SSD comes nearly at the price of a small car, you expect a lot, performance-wise. At least I did when I got my hands on two drives from HP’s enterprise performance series. Read on to find out if that hefty price tag is justified.

Did I mention I love the new Task Manager in Windows 8? It is brilliantly designed, conveying tons of meaningful information while looking very good. This article is not about Task Manager, though, but about Windows 8 - its Storage Spaces functionality, to be exact. But I will be using Task Manager to analyze the performance of Storage Spaces. And with that, we are back where we started.

Doesn’t every IT pro dream of finding a secret switch, a switch that increases clock speed, doubles the amount of RAM or makes the PC boot faster? Some do, and I admit I was fascinated when I heard that changing a simple boot option would significantly speed up startup time. I made some tests which confirmed what I had heard and blogged about my findings. A lot of people picked up that post, I was happy and everything was great - until I found out I was wrong.

Problem Firefox (3.6.13) intermittently freezes. This happens during scrolling, text input, basically everywhere in the user interface, rendering the browser nearly useless. Analysis While browsing amazon.de I created a log of Firefox’s activities by recording system activity for 85 seconds with Sysinternals Process Monitor. I then filtered the log to include only Firefox activities. Clicking on Tools -> Process Activity Summary I got:

Normally, finding the cause for high CPU utilization is easy - just start Task Manager. But what if the component consuming CPU cycles is a driver that runs in the kernel? In that case, there is no regular process Task Manager could attribute the usage to. You will see the “System Idle Process” at around 98%, but the “Performance” tab might indicate 50% CPU usage. How can that be?

Here are some very simple guidelines that help determine how much memory a particular server actually needs in order to perform well. Of course, these are just rules of thumb, but nevertheless they might come in handy.

Even with the most meticulous design, the day will come when your farm’s capacity is not sufficient any more. User numbers increase, applications become more resource-hungry and the amount of data to be handled increases steadily. So what do you do? Simply more of the same, i.e. buy more servers and add them to the farm? That is one way of increasing capacity, but it is not the only one and therefore may not be the best.

Update: The ADM file can now be downloaded here. I recently came across a post in the Windows Server Performance Team’s blog that lists several registry values which can be used to tune Explorer’s SMB performance by modifying the following: