Machine Creation Services RAM Cache and XenServer IntelliCache


As I was discussing the storage optimization capabilities in the Machine Creation Services vs Provisioning Services debate, I mentioned the use of a XenServer RAM-based read cache. This can be misunderstood as XenServer IntelliCache (a mistake I’m sad to say I’ve made in the past). XenServer IntelliCache (released with XenServer 5.6 SP1) and XenServer RAM Cache (released with XenServer 6.5) are two different capabilities of XenServer, both of which tries to reduce the  IO impact on shared storage. Let’s walk through different deployment scenarios with Machine Creation Services in XenApp and XenDesktop 7.9. Scenario 1: Shared Storage on any Hypervisor … Continue reading Machine Creation Services RAM Cache and XenServer IntelliCache

You don’t need to be a rocket scientist to see the value in RAM Cache


A few years ago, we replaced all of our windows in our home (I’m talking about the panes of glass you look through, not the operating system). We, of course, talked with a few different companies who stopped by, went through their product portfolio and brought along samples. One demonstration stuck with me. The sales person, placed his sample window flat on the ground and stood on it, demonstrating the strength of the window. I immediately started thinking, “That was totally wicked” and “I wonder if it has ever shattered before”. As the practical part of my brain kicked in, … Continue reading You don’t need to be a rocket scientist to see the value in RAM Cache

ESG Lab Spotlight Report: Up to 80% Reduction in Storage Cost for VDI and RDS


You’ve heard the news, you’ve seen the videos, and now the storage savings have been verified! According to an ESG report, the new RAM Cache with Disk Overflow feature, included in the XenApp and XenDesktop 7.6 release, has the potential to reduce storage costs by 80% or more. Now before you stop reading thinking this is too good to be true, think about the storage cost problem for a moment. Storage costs associated with RDS/VDI solutions is for throughput and not space. We need to have enough throughput or IOPS so the user experience doesn’t suffer. And believe me, it … Continue reading ESG Lab Spotlight Report: Up to 80% Reduction in Storage Cost for VDI and RDS

PROOF[Video] – New XenDesktop and XenApp Storage Optimizations Does Improve the User Experience


I’ve written and seen numerous blogs/tweets about how great the new storage optimization feature is for XenApp and XenDesktop. I’ve read how this feature can reduce IOPS from an average of 15 IOPS per Windows 7 user down to 0.1 IOPS. I’ve read how this feature functions by creating a small RAM buffer within each VM. I’ve seen tweets showing crazy IOPS numbers on using standard, spinning disks. In fact, I’ve done some of this analysis and was completely blown away by the results. But who cares? Who cares if my IOPS are reduced by 99%? Unfortunately, unless you are … Continue reading PROOF[Video] – New XenDesktop and XenApp Storage Optimizations Does Improve the User Experience

Does Cache Trump IOPS


With desktop virtualization, we hear more and more about how important IOPS are to being able to support the virtual desktop. I’ve had a few blogs about it and plan to have a few more. What I wanted to talk about was an interesting discussion I recently had with 3 Senior Architects within Citrix Consulting (Doug Demskis, Dan Allen and Nick Rintalan).  There are 3 smart guys who I talk to fairly regularly and the discussions get quite interesting.

This particular discussion was no different.  We were talking about the importance of IOPS, RAID configs, spindle speeds with regards to an enterprise’s SAN infrastructure. (Deciding if you are going to use a SAN for your virtual desktops is a completely different discussion that I’ve had before and Brian Madden had more recently). But for the sake of this article, let’s say you’ve decided “Yes, I will use my SAN.” If your organization already has an enterprise SAN solution, chances are that the solution has controllers with plenty of cache. Does this make the IOPS discussion a moot point? Continue reading “Does Cache Trump IOPS”

Dear Architect, is my write cache estimate correct?


The latest question into the Ask the Architect mailbag comes from Andy.  Andy is creating a Provisioning services design for an environment based on Windows Server 2008, with the write cache stored on a NetApp share.  Andy’s question is if the write cache estimates are correct.  Basically, Andy is estimating 650 MB write cache per virtual desktop.  He achieves this by taking the assigned RAM and multiplying it by 25%. First, using Windows 2008 is great for Provisioning services as this provides the largest system cache for the vDisk, which will speed up delivery as local disk reads are not … Continue reading Dear Architect, is my write cache estimate correct?