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Top 5 Planet V12n blog posts week 20

It's been a while since the last Top 5 has been released. My apologies, but I attended the VMware Technical Summit, was on a holiday for a week in Italy and two close relatives passed away. Anyway it is Sunday again and tomorrow a fresh new weeks start… no apologies any more. We will continue with the Top 5 as of this week again. It took me a while to go through the immense list of articles, but I guess the following 5 stood out. 

  • Bob Plankers – What are P-states and how do I use them in vSphere? 
    VMware vSphere 4 added the ability to take advantage of Intel SpeedStep and AMD PowerNow! CPU power management features. These features are commonly known as “Dynamic Voltage and Frequency Scaling” or DVFS, and let an OS cooperate with the CPU to reduce power consumption by reducing the frequency of the CPU and the voltage at which it is operating. It reduces these things in preset tiers, and these tiers are known as P-states. On Intel CPUs they are trademarked as “SpeedStep” and on AMD they are either “Cool’n'Quiet” or “PowerNow!”
  • Bouke Groenescheij – Shares: Low-Normal-High
    Well, try to stay away from multi core VMs. If you are running multicore VMs, don't overcommit (at least not too much) and put them on a dedicated cluster. Why not overcommitting? Well, duh, you gave it multiple CPUs, so apparently those VMs need to do some processing which is very important. And since it's that important, don't overcommit. Should make sense. Else give it one vCPU. Also, try not to use the somewhat extreme 'low-normal-high' share setting. I would say: "If a VM is more important, use a custom setting of 1200 shares/vCPU. If a VM is less important, use a custom setting of 800 shares/vCPU". That way the ratio between them isn't that extreme and nature is more balanced.
  • Frank Denneman – Resource Pools Memory Reservations
    If a cluster is under-committed the VM resource entitlement will be the same as its demand, in other words, the VM will be allocated whatever it wants to consume within its configured limit.
    When a cluster is overcommitted, the cluster experiences more resource demand than its current capacity, at this point DRS and the VMkernel will allocate resources based on the resource entitlement of the virtual machine. Resource entitlement is covered later in the article.
  • Scott Sauer – VMware Acquisitions – What’s it all mean?
    There has been a lot of activity here at VMware with acquisitions and partnerships over the past few months. A fellow engineer at VMware summarized a lot of these acquisitions and how they are meaningful to VMware as an organization. I wanted to share this information because I think it provides people with a better understanding of where we are going as a company and the overall strategic vision of VMware (Thanks again Andy!).
  • Steve Kaplan – Calculating the optimal Microsoft SQL licenses for virtualization
    The ability to consolidate multiple SQL instances onto a single host combined with application server license mobility rules generally make either SQL Server Enterprise or SQL Server Datacenter the best choice for a vDC. A 2-CPU VMware vSphere host, for example, running two licenses of SQL Server Enterprise could run up to eight instances of either SQL Server Standard or Enterprise. Additionally, these instances can either be VMotioned to another host in the cluster or even utilize the continuous availability of vSphere Fault Tolerance without requiring additional SQL licensing for the target host.
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Duncan Epping

About Duncan Epping

Duncan is a Chief Technologist working in the Storage and Availability Business Unit at VMware, serving as a partner and truster adviser to EMEA customers. He is the co-author of several books, including the vSphere Clustering Deepdive series and Essential Virtual SAN. He is the owner and main author of virtualization blog yellow-bricks.com.