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Supplemental Data – for vSphere Install Configure Manage Class

This page is intended to be a single source for data to supplement the material covered in the VMware vSphere Install Configure Manage class.  It is based mostly on Frequently Asked Questions  from students, who attend this class.  It provides details and URLs on items that are not covered  in detail in the class, but are necessary for an IT professional to be successful in implementing and supporting vSphere.

vSphere Editions and Licenses

Paravirtualization vs Full Virtualization vs Hardware Assist

Differences in ESX and ESXi

Upgrading from vSphere 4 to vSphere 5

Distributed Virtual Switches (dvSwitches)

These are only briefly discussed in the vSphere ICM class.  Here is a video on dvSwitches (drill to the Videos section in the middle of the page and choose the video on Networking Distributed Switch ).   And here is a webpage  providing an overview and details on dvSwithces.

Choices for virtual Ethernet Adpapters:

new choice in vSphere 5 = e1000e:

Time Synchronization Strategies

Virtual machines tend to lose track of time, unless they are configured to synchronize to a good time source.  VMware Tools may be use to synchronize a VM’s guest O/S to the time on the ESXi host, or a more traditional method, such as the Windows time service may be used to synchronize with an Active Directory domain controller.  VMware has published Time Keeping Best Practices for virtual machines and details for Time Keeping in Virtual Machines

Beacon Probing,US&cmd=displayKC&externalId=1005577

NetApp:  Comparison of FC, iSCSI, and NFS at various bandwidths

This document provides the results of tests performed by NetApp on NetApp storage using FC, iSCSI, and NFS access.  The goals of the test was not to measure maximum performance, but instead to measure performance under low, medium, and high workloads.  The results indicate:

  • vSphere 4 natively provides great improvement over VMware Infrastructure 3 for iSCSI and NFS performance
  • iSCSI and NFS performance is now within 5% of FC performance
  • all three options are viable for productions workloads

Test results –

Storage Protocol Comparisons (VMware Blog)

iSCSI Considerations – a multi-vendor collaboration

Here is a link to good whitepaper on configuring iSCSI written as a collaboration from multiple vendors:

iSCSI – port binding

Here is a simple illustration of utilizing multiple vkernel ports on the same virtual switch, but separate virtual port groups, and port binding to distribute I/O manually across multiple paths:

NFS Considerations – a multi-vendor collaboration

vSphere Storage Concepts and Troubleshooting

Here is some really good information on understanding how to analyze and troubleshoot Storage performance issues in vSphere.:

Changed Block Tracking

Some vSphere features rely on Changed Block Tracking, which is a vmkernel feature introduced with vSphere 4.0

VMFS Track Alignment

Improper alignment of a VMFS partition can certainly result in poor performance of applications.  Typically, using the vSphere Client to create VMFS datastores result in proper alignment, but this may not always be the case.   Here is a document that discusses the impact and the steps to ensure proper alignment; and

Guest O/S Track Alignment:  Likewise, the guest operating system’s file system should also be properly aligned to ensure the best performance.  Typically, this rule should only be applied to the non-system disks.  For example, when adding a second disk to a Windows server that is intended to be used to install application software, the following Diskpart commands could be used:


list disk

select disk 1

create partition primary align=1024

assign letter=E

format fs=ntfs unit=64K label=”Applications” nowait

In this example, the disk to be partitioned is Disk 1 (the first disk is Disk 0), its beginning partition is offset at 1024 KB, its drive letter is E:, and unit of allocation is 64K.

Here is a good reference:

VMFS and SCSI Reservations

Certain activities within a VMFS datastore may result in using SCSI Reservations to temporarily lock the underlying LUN and impacting other hosts sharing the datastore.  Here is a reference:


Here is information about a free tool from Dell that easily extend the size of partitions within Windows 2003 servers, including VMs:

This is the same tool that is currently used in VMware certification course labs.

Virtual Disk options for VMs in vSphere:

ESX servers use monolithic v-disk files (vmdk files) that are pre-allocated to the configured size. These files do Not grow. Having said that, templates can be stored in various formats and other Vmware products allow additional formats. Here are the options:

  • Thick – Single file, preallocated to max size.
  • Zeroredthick – single file, prealloacted to max size, but not zeroed out at creation. Instead the VM will zero out any existing data in the virtual disk later.
  • Eagezeroredthick – single file, prealloacted to max size, and zeroed out at creation, which takes longer than zeroedthick. – NOTE: this is required for VMs protected by VMware Fault Tolerence
  • Thin – not preallocated, instead the file is expanded and zeroed out on demand later.
  • 2gbsparse – split into multiple files of 2G or less, compatible with other VMware platforms. This is required and provided by default for NFS storage.

Reclaiming (Shrinking) Thin-Provisioned Virtual Disks

Thin provision virtual disks do not automatically shrink the virtual disk files whenever files in the virtual disk are deleted.  Here is a link that provides a manual method for shrinking the disk:

Storage VMotion – Raw Device Mappings (RDM)

Storage VMotion can now be used to migrate data from a raw device mapping in virtual compatibility mode to a VMDK file.  To do this, choose the Advanced option in the Migration Wizard, choose a VMFS datastore to migrate the raw device, and choose one of the Thick or Thin options for the type.  Additionally, the selected target VMFS must not be the same VMFS as where the rdm.vmdk file (the raw device metadata file) currently resides.  For details, see this knowledge base article.

vCenter Converter Standalone

the standalone version has more features than the Server component used in class.  For example, it provides options to automatically shutdown the source server, re-synchronize final data changes, and boot up the new VM.

User Guide:

Hardware Health Monitoring / CIM

NUMA Considerations

Many newer CPUs use NUMA architecture.  Here is  good document concerning NUMA and large VM configurations:

Memory Management in vSphere

ESX Server provides a Ballooning Mechanism to borrow RAM from a rich VM and give to a poor VM.  Here is a link to a good, detailed article that includes an explanation of ballooning and other memory related information.

Memory compression – New Feature in vSphere 4.1

The vmkernel now looks to compress memory in a memory compression cache within the VM.  This step exists just prior to vm swapping step:

vCenter Linked Mode:

Using P2V (VMware Converter) on Domain Controllers

Typically, I prefer Not to P2V domain controllers, but instead use dcpromo in a Windows VM, then decommission old physical domain controllers.  Here are links with details on the challenges and options for performing P2V Migrations of domain controllers

VMware High Availability and Fault Tolerance

VMware vSphere HA has been rebuilt from the ground up by VMware in version 5.  Originally, it was simply a modified version of Legato AAM and it have several annoying elements.  But, now that it has been re-architected it should be much more resilient and flexible than in previous version.  For example, restarting HA for the entire cluster should only take a minute or so.  And, since it uses a single master approach, it is no longer limited to supporting a maximum of 4 concurrent host failures.  The vSphere Availability Guide contains details.

Here is a good Fault Tolerance White Paper.


They vSphere Web Client can be used to define and assign tags to objects in vCenter.  It allows the user to filter and search based on tag values.  The first step to create a new tag is to create a Category and set the Cardinality (number of tags in the category that can be assigned to a specific object).  See this video on object tagging.

VMWare Data Recovery

Document with information for configuring and supporting VDR:

VMotion – Under the Covers

What really happens during a VMotion migration?  You will likely see that the following links provide more detail than the descriptions provided in the course materials:

VMotion CPU Compatibility

Here is a good link for CPU Compatibility for VMotion:

Commands and scripting

VMware created a set of commands for the ESXi command shell.  The legacy commands begin with the string “esxcfg-“, such as esxcfg-nics and esxcfg-vswitch.  Today, VMware provides a single command for almost all purposes.  The command is esxcli, which involves a complex set of arguments.  VMware prefers that such commands are run remotely using the vSphere Command Line Interface (vCLI), which can be installed on an administrator’s desktop (Windows or Linux), or can be run within a deployed VMware vSphere Management Assistant (vMA) virtual appliance. Here is some information to get started:


Several automation tools are available to function with vSphere.  The most powerful tool is probably the PowerCLI.  Generally, if any vCenter task requires automation beyond what the vSphere client provides or if the client does not adequately provide a desired function, the first place to turn to may be PowerCLI.  It provides a command set that allows the creation of scripts to call operations to be run in vCenter and the ESX servers.

Image Builder

In order implement custom device drivers, plug-ins, and other extensions, the VMware Image Builder can be utilized to merge these items with the standard VMware ESXi installation files into a single ISO file.  Here is a decent article to explain the process.

Visio Stencils

Here is a decent resource for downloading vSphere Stencils for vSphere:

vSphere Orchestrator

This product is mentioned in the vSphere ICM class, but no real details are provided.   It is intended to provide a means to interface vSphere with other VMware and 3rd party products, allowing automation.  To gain familiarity, begin by reviewing the Overview and documentation found at this link:

good blogs, websites, etc. focused on virtualization

Recommended books:

Recommended Reading from VMware:

These are good guides from VMware to read to reinforce the material covered in class.  These PDF files can be found at the VMware vSphere 5 Documentation Center:

  • vSphere Installation and Setup guide
  • vSphere vCenter Server and Host Management
  • vSphere Networking
  • vSphere Storage
  • vSphere Resource Management

Preparing a vSphere Lab to Gain Hands-on Experience and Prepare for VCP Exam

For students, who need a lab to gain more hands-on experience with vSphere, here is some information that may be useful for implementing vSphere within VMs on a desktop.  One key is to implement a Virtual Storage appliance and another is to install ESXi in VMs

Virtual storage products

This link provides a list of vm-based storage products that may be useful for proof of concept labs, where shared storage is required, but a real SAN does not exist:

How to install ESXi in a VM on vSphere 5


Here is a tool that may simplify deploying a nested vSphere infrastructure (running ESXi in VMs) in a lab environment for those wanting to practice for VCP or gain familiaraity.

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