Scott Drummonds on Virtualization

Custom Alarms for VMware SIOC

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Over a year and a half ago I previewed VMware’s unreleased feature, Storage IO Control (SIOC).  SIOC creates new intelligent latency metrics to evaluate the health of VMFS volumes.  The same latency measurements are used in storage DRS, which VMware released in vSphere 5.  While automated performance correction is great, vCenter should warn VMware admins when latency crosses defined thresholds.  Custom vCenter alarms can do this.

With hardest work of making vSphere 5 generally available behind him, one of VMware’s engineers, Balaji Parimi, recently sent me scripts he wrote to create SIOC alarms.  These alarms can be used to tell administrators that SIOC is throttling some virtual machines to save high priority applications from ailing datastores.

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vShield Clarification


A couple of weeks ago I wrote on vShield. As I said then, the Asia Pacific and Japan vSpecialists have spent a lot of time on this wonderful product. We love it. The purpose of my blog entry was to highlight a best practice that would avoid an annoying issue. That issue is that vShield App installation on ESX hosts running a vCenter virtual machine can disconnect vCenter from the network. The workaround–documented in the vShield Administration Guide–is to run vCenter and vShield manager on a management cluster. Case closed. Well, not yet.

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vShield, vCenter, and Management Clusters


I recently tweeted looking for VMware customers using the vShield products in production. There was very little response. It seems that vShield Edge and App are barely being used at all in production. It is possible that some rough patched need to be sanded down to polish vShield to its appropriate luster. But if you are not playing with these products now, you owe it to yourself to download the trial versions.

Our fantastic APJ vSpecialist organization has been spending with vShield. Many of us believe vShield to be one of the most exciting editions to the VMware portfolio in a long time. It is simple, elegant, and very powerful. But there is a very big danger with vShield: improper use can disable the network connection of vCenter virtual machines. Fixing this problem is not intuitive.

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vCenter Custom Alarms: Instruction, Tips, Tools


Half a year ago the Asia Pacific vSpecialist team made a fantastic acquisition in one David “Two Screws” Lloyd. David previously worked for a wonderful VMware and EMC customer in the UK and moved back to Australia. That is when we jumped on the opportunity to snap him up. In working with him in the labs recently, I have come to realize that David has incredible depth and breadth in the space of virtual infrastructure management.

Recently David sat down to share his tips on setting up alarms in vCenter. Most of VMware’s customers understand the power of custom alarming but few harness its value. Using an example of storage path failures, David created a video that walks its audience through the process of configuring a custom alarm using a tailor made executable that generates useful logging message in the vCenter OS’s event log.

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Alternative to DRS


Now that I am six months removed from VMware, I will admit that we executed poorly in the space of performance management.  I know that there is intense work going on right now in acquisitions, unification of performance management tools, and vCenter improvement through folding in vscsiStats and esxtop data.  But in the area of performance reporting and visualization, VMware’s success has been minimal.  VMware hopes its acquisition of AliveVM will plug part of this gap but today it is safe to say the field is wide open for VMware’s partners.

This morning one such partner, VMTurbo, gave me a demonstration of their offering in this field.  Their product provides an obvious improvement on vSphere’s performance visualization capabilities.  But given the state of VMware’s visualization capabilities virtually any graphical front-end provides an improvement.  But what really set off my imagination were two features I had not seen before:

  • A third-party alternative to DRS.
  • Cross-cluster resource optimization.

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Maximum Hosts Per Cluster


I just returned from a one week vacation to a warm sunny beach on a small island not too far from Singapore.  Even on my vacations my conversations often migrate to technology and my travel mate is an old friend and current employee at VMware, Dave Korsunsky.  Sitting by a pool with a cocktail in hand at a fantastic hotel I asked my friend, “what is the right number of hosts per DRS/HA cluster?”  Great conversation for a vacation, right?

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Storage Consolidation (or: How Many VMDKs Per Volume?)


Part of the performance best practices talk I co-presented at VMworld in San Francisco and Copenhagen focused on answering the question, “How many virtual machines can be placed on a single VMFS volume?”  There are a lot of theories as to a best answer.  It will not surprise you to learn that no single consolidation ratio works in every environment.  Your workloads will influence the maximum consolidation.  But we know enough about how ESX virtualizes storage to provide guidance as to the right storage consolidation ratios.

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Performance Troubleshooting Made Simple


I have struggled for years to give VMware’s customers a framework for diagnosing performance problems. People want a simple system to troubleshoot the unknown sources of poorly performing applications. The best attempt at documenting such a flow is Hal Rosenberg’s document on vSphere performance troubleshooting. Elegant as it may be, Hal’s document remains complex for the novice VI administrator.  And it is because that document is so complex that performance people maintain their job security. 🙂 But in an effort to further obviate my own job, I will try and generalize the troubleshooting flow to add more clarity to the process.

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How Many Virtual CPUs Per VM?


Virtual machine sizing is a tricky issue for many VMware administrators. It is important to find the right number of virtual CPUs to maximize application performance and minimize wasted CPU cycles. The optimal number of vCPUs can never be easily identified. But I can offer a few suggestions to help get this number right.

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Optimizing Memory Utilization


My recent series of blog articles have discussed ESX memory management the the performance specter of host swapping. My last article attempts to correct the misconception that VMware recommends against over-commit memory.  In that article I suggested that memory over-commit is requirement in optimizing memory utilization. Today I want to provide a specific example to show why this is true.   I am have also included tips for identifying host swapping in your environments.
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