VMware vSphere Fast Track Day#3 – Lessons Learned

This is my third day attending VMware vSphere Fast Track training at Jean Cordier Academy in Leuven, Belgium.
Day one and day two brain dumps are available here and here,  It is time to sum up what I have learned today in no particular order.

  • Coffee in big boilers still sucks, but that you already know by now 🙂
  • My trainer, Bert De Bruijn,  has an ‘interesting’ sens of humor… I will have to tell you about that in another post 🙂
  • VMware Tools must be installed. Why it is mandatory?
    • Contains many enhanced drivers for the network, SCSI controllers, memory management (Memory Balloon driver), SVGA driver,
    • Support synchronization of time in the guest operating system with time on the host,
    • Automatic grabbing and releasing of the mouse cursor,
    • Copying and pasting between guest and host,
    • Improved mouse performance in some guest operating systems,
    • Supports for application HA by exchanging heartbeat with VMware HA.
  • A Template is a master copy of a VM used to create and provision new VMs.
    • It doesn’t have a On/Off  button,
    • To update the Template you must convert it back to a VM, make the appropriate changes and then convert back to Template.
  • Cloning a VM is an alternative to Template. Use what best fits your needs.
  • Microsoft Sysprep:
    • Deploy in C:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter\sysprep\,
    • Sysprep is built-in for Vista, Windows 2008, Windows 7,
    • vSphere 4.0U1 supports Guest Customization of Vista, Windows 2008, Windows 7.
  • vCenter Converter plug-in is used to import and export or reconfigure physical or virtual machine or system images:
    • Disk-based cloning transfer all sectors from all disks and preserver all volume metadata,
    • Volume-based cloning is performed at the file or block level. Note that file level is noticeable slower than block level and more flexible.
  • CPU and memory ca be hot added while the virtual machine is powered on as long as the OS supports this task and VMware Tools must be installed as well.
  • Hot extend is used to increase the size of a virtual disk. Use Diskpart or Disk Management GUI to extend within the OS.
  • RDM is a file that has a .vmdk extension but the file contains only disk information describing the mapping to the LUN on the ESX/ESXi.
  • RDM compatibility mode can be:
    • Physical compatibility mode allows the OS to access the hardware directly. Required for Microsoft MSCS.
    • Virtual compatibility mode allows the VM to use snapshots and other advanced functionality.Cloning, convert to Template or migrate copying the disk requires a copy into a VMDK.
  • You can delay the boot process within the Virtual Machine Properties.
  • Paravirtualization is a virtualization enhancement where a guest OS is aware that it is running inside a VM
    • Virtual Machine Interface (VMI) is a paravirtualization standard that enables improved performances for VMs capable of using it.
    • Only few Linux distros use it.
    • Microsoft OS’es don’t,
    • That enhancement may phase out in future version of vSphere.
    • A VM with paravirtualization enabled that is  powered on or suspended cannot be migrated.
    • DRS doesn’t support it,
    • Requires a virtual PCI card.
  • Disable acceleration (a feature in the VM Properties) can help troubleshooting some application hanging at start up. Once the application is fine, tick it out.
  • Virtual Machine Snapshots:
    • If you leave it growing, it wont be bigger than the size of the VMDKs. That being said, never leave it growing unattended. vSphere has specific alarms for that.
    • It capture the entire state of a VM, this includes:
      • Memory state if you tick that in and the VM is obviously powered on.
      • Settings state,
      • Disk state.
    • You can quiesce guest file system too:
      • It can use the Sync driver that is installed with VMware Tools. A separate service called “Sync Driver.” The Sync driver shows up in Windows logs as “LGTO_SYNC”.
      • It can use VSS if  the VM operating system runs Windows 2003, Vista, 2008…
    • Snapshot manager allow to perform 3 tasks:
      • Delete which actually means commit the snapshot data to the parent, then remove the selected snapshot,
      • Delete All, this task commits ALL the intermediate snapshots to the base disk and remove all existing snapshots,
      • Go to allows you to revert to a particular snapshot which become the current snapshot
    • A VM Snapshot File consists of:
      • Memory state (.vmsn),
      • Description file (-00000#.vmdk),
      • Delta file (-00000#-delta.vmdk),
    • Snapshot List Files (.vmsd) keeps track of the VMs snapshots.
  • VMware vAPP is a multitier application service that you can manage as a single inventory item. DRS has to be turned on on clusters, not on a single ESX/ESXi host.
  • Migrating a Virtual Machine is the process of moving a VM from one host or storage location to another. The type of migrations:
    • Cold – VM is powered off, different CPU families allowed,
    • Suspend – VM is suspended, must meet CPU compatibility requirements,
    • VMware vMotion – VM is powered on, must meet CPU compatibility requirements, shared storage required!
    • Storage vMotion – Migrate just a VM’s file whilst the VM is powered on, to a difference datastore.
      • Is storage type independent,
      • Support migrating RDMs to RDMs,
      • Provides the option of thin disk,
      • Can convert RDMs to VMDKs,
      • Non virtual disk files are copied to the new VM home using Network File Copier (NFC).
      • vSphere enable Changed-block tracking (CBT) on the VMs disk to track changes to the disk when performing the Storage vMotion.
    • Limitations:
      • VM with snapshots cannot be migrated,
      • VM mus be powered off to concurrently migrate to another host and datastore,
      • Up to 4 concurrent Storage vMotion migrations can occur.
  • Access Control system allows the vCenter Server adin to specify which users or groups can perform which actions on which objects. It is defined using the following concepts:
    • Privilege, that is the ability to perform a specific action or read a specific property,
    • Role, that is a collection of privileges (there is no ‘deny’). It provides a way to aggregate all the individual privileges that are required to perform a higher-level task,
    • Object, that is an entity upon which actions are performed.

This is it for today. Tomorrow we will see FT, DRS, and HA. Come back for the fourth part…


About PiroNet

Didier Pironet is an independent blogger and freelancer with +15 years of IT industry experience. Didier is also a former VMware inc. employee where he specialised in Datacenter and Cloud Infrastructure products as well as Infrastructure, Operations and IT Business Management products. Didier is passionate about technologies and he is found to be a creative and a visionary thinker, expressing with passion and excitement, hopefully inspiring and enrolling people to innovation and change.
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