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Scaling up your virtualization solution on 8-socket HP ProLiant Servers

These days, when wearing my “Linux planner” hat, and with Virtualization being the “phrase that pays”, I’m often asked to help provide guidance on how to best take advantage of the technology included in our 8-socket HP ProLiant server offerings for Linux based virtualization solutions like Red Hat Enterprise Virtualization or Suse Linux Enterprise Server Xen (there’s a plethora of information out there about VMware ESX/ESXi 3.5.x and vSphere 4.0, so I’m not going to talk about that, this time around.)


The problem I’ve had, until recently, was providing actual – objective - data as a means to help illustrate my points.  For instance, I could not clearly illustrate how a snoop filter on the CPU interconnect can improve the linearity of the workload scalability in a virtualized environment (see Fig. 1).


Fig. 1: Average response time with pinned vs. un-pinned processors


 Fig. 1: Average response time with pinned vs. un-pinned processors


I was unable to demonstrate benefits of the NUMA aware scheduler that the Linux kernel uses and how it does improve performance. (In figures 2 and 3, it’s represented by the improvement in average response times from the web-servers included in the workload) when your workloads run with memory interleaving disabled in the system BIOS – see Fig. 2. Unless, for support reasons, your application vendor explicitly tells you otherwise.


Fig. 2: Average Response Times - Non-interleaved Memory Config


Fig. 2: Average Response Times - Non-interleaved Memory Config


Fig. 3: Average Response Times - Interleaved memory


Fig. 3: Average Response Times - Interleaved memory


I also used to have a hard time explaining how and why to tune the Linux kernel for these systems. For instance, I only suspected how little (none) tuning of the host platform is required in order to drive pretty significant numbers of guests  (98) in these environments - see Fig. 4. But, if you engage in some very minor tuning activities of the network stack, how those very same workload performance results can be extended even further (to 256 guests) – see Fig. 5:


Fig. 4: The system has not been tuned beyond it's "out of the box" state.


Fig. 4: The system has not been tuned beyond it's "out of the box" state.


Fig. 5: System is tuned and exhibiting linear scalability to 256 KVM guests


Fig. 5: System is tuned and exhibiting linear scalability to 256 KVM guests


As part of a joint documentation effort with Red Hat, all of the data collected has been brought together in a Reference Architecture document  - “Scaling RHEL 5.4 + KVM up to 256 Guests" available for free from Red Hat’s website.


We obviously picked the guest density to prove a point about the platform, however it’s worth mentioning that 256 guests does not represent the upper bound for the platform. It only represents where we thought the density went (far) beyond what is reasonable to expect in a production environment this day in age.


Contributed by Thomas Sjolshagen (Strategic Planner for Linux and Virtualization on scale-up x86 servers)

KVM or iLO?

By Ankit Gupta.  KVM switches play an important part in designing the data center solution where you can have multiple server access at a given  point of time. Many new technologies have evolved in the past 5 years and we have always believed that KVM is not a competitive, but a complementary solution to the existing and advanced data center management. Take a minute to tell us how it has been realized in you data center space. Is KVM a complementary solution to advanced technology such as Integreated Lights Out (iLO)?

 

What is a KVM?

By Ankit Gupta.


Using multiple computers in a restricted area can be tricky as they often need their own peripheral devices directly attached, such as a keyboard, monitor, and mouse - even though these devices may be used rarely. Buying multiple devices can get expensive, the running costs can be high and they take up a lot of space.


A Keyboard, Video and Mouse (KVM) switch can help alleviate this problem by providing a central hub into which extension cables can be run out to each participating computer for various peripherals, but commonly the keyboard, video display and mouse. It is a good choice when you need to access many computers independently. 

Typically, KVM switches can control up to as many computers you want to manage at a time, What’s more, the switch can be used for multiple computers that are remotely located. All you need is a single central keyboard, video display and mouse and an onboard selection mechanism that will choose the computer that is to be controlled. Think of it as being a bit similar to one of those remote controllers that can talk to your TV, DVD and Satellite box.

Here is an interesting point. Many KVM switches can also emulate peripherals so that the computers do not get confused and they think that they are connected to a keyboard, video and mouse at all times. More recent KVM switches can also link up USB ports and speakers and can utilize the network to avoid the need for a physically connected central keyboard, mouse and video display. 


 

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About the Author(s)
  • I am part of the embedded software management team doing UEFI, Scripting tools (STK, PowerShell), etc
  • I am part of ISS Product Marketing, currently managing couple of dual processor ProLiant servers.
  • More than 25 years in the IT industry developing and managing marketing programs. Focused in emerging technologies like Virtualization, cloud and big data.
  • Delisa Johnson currently leads successful, corporate events for HP Servers and is established as the go-to person for business unit communications regarding launches, executive meetings, wins and business updates.
  • I work within EMEA ISS Central team and a launch manager for new products and general communications manager for EMEA ISS specific information.
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  • Luke Oda is a member of the HP's BCS Marketing team. With a primary focus on marketing programs that support HP's BCS portfolio. His interests include all things mission-critical and the continuing innovation that HP demonstrates across the globe.
  • I work in the HP Servers marketing group, managing a marketing team responsible for marketing solutions for enterprise customers who run mission-critical workloads and depend on HP to keep their business continuously running.
  • Global Marketing Manager with 15 years experience in the high-tech industry.
  • I’ll be blogging about the latest news and enhancements as it relates to HP Moonshot.
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