XenServer PVS Accelerator Cache Sizing


How large should we make our PVS Accelerator cache? Too large and we waste resources. Too small and we lose the performance.

Let’s take a step back and recall our best practice for sizing the RAM on Provisioning Services.  We would typically say allocate 2GB of RAM for each vDisk image the server provides.  This simple recommendation gives the PVS server enough RAM to cache portions of the image in Windows system cache, which reduces local read IO. So for a PVS server delivering

  • 1 image:  we would allocate 2GB of RAM (plus 4GB more for the PVS server itself)
  • 2 images:  we would allocate 4GB of RAM (plus 4GB more for the PVS server itself)
  • 4 images:  we would allocate 8GB of RAM (plus 4GB more for the PVS server itself)

Easy.

Let’s now focus on the XenServer portion of PVS Accelerator. If we use RAM as our PVS Accelerator cache, how many GB should we allocate?

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Provisioning Services Accelerator


An interesting new feature was included with the XenServer 7.1 release: Provisioning Services Accelerator.

In a single sentence,

PVS Accelerator overcomes PVS server and network latency by utilizing local XenServer RAM/Disk resources to cache blocks of a PVS vDisk to fulfill local target VM requests.

Take a look at the demo video to see:

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Sizing Windows 10 and Windows 7 Virtual Machines


After reviewing all of the scalability tests we conducted over the past few months, I thought it was time to revisit the recommendations for sizing Windows 10 virtual machines.  I also reached out to Nick Rintalan to see if this is in line with what is currently being recommended for production environments (if you disagree, blame him 🙂 ). A few things you will notice Windows 7 and Windows 10 recommendations are similar.  Microsoft’s resource allocation for both operating systems are similar.  The Windows 10 and Windows 10 scalability tests resulted in similar numbers. Density – Experience: For some of … Continue reading Sizing Windows 10 and Windows 7 Virtual Machines

Microsoft Windows 10, Citrix XenDesktop and Logon Time


How long does your Windows 10 logon take? Logging into my lab, my logons felt long. True I’m not using server-level hardware that you would see in production, but my logon times felt too long because I don’t have logon scripts, complex group policy preferences, or even massive profiles. After reading the Rule of 30 blog by Nick Rintalan, I decided to investigate. I was interested in knowing if all of the Windows 10 optimizations I previously blogged about would have an impact Default apps Services Scheduled tasks User Interface Runtime Release ICA My first test was looking at the … Continue reading Microsoft Windows 10, Citrix XenDesktop and Logon Time

Provisioning Services Read Cache


As you can see, I’ve spoken numerous time about the Provisioning Services RAM Cache with Disk Overflow capability. Windows 10 IOPS Video Proof Reducing IOPS to 1 Read/Write Ratios XenDesktop 7.5 IOPS Digging deeper into IOPS ESG Spotlight on IOPS So yes, I like talking about this topic.  But now, I’m going to talk about something very slightly different… Cache 🙂 While I was working on capturing some images for my Citrix Synergy 2016 Tech Update session, I saw something interesting. I started my lab, started my Provisioning Services server and launched a Windows 10 virtual desktop.  According to the … Continue reading Provisioning Services Read Cache