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Friday, 24 August 2012

vMA5 and IP Allocation Policy

The vMA should now be deployed to your vSphere cluster and you will end up with a new VM in you inventory. But at this point you cannot power on the VM since there is no IP pool configured. If you try to boot the VM will you get an error message like this:

Cannot initialize property ‘vami.DNS0.vSphere_Management_Assistant_(vMA)’, since network ‘VM Network’ has no associated IP pool configuration.

To get the vMA started you have to disable the vApp Option check this Demo:



vMA5 Deployment Demo

vMA5 vi-admin Password Complexity Issue

In vMA5 you won't be able to set the password for the vi-admin unless and until your password is complex. I spent approx. 30 Minutes to assign the password to vi-admin account. Here is screenshoot of errors that i was getting at that time.

Then i configured Axtm123!# as the password then as soon as my vMA appliance was booted i logged in here by using vi-admin as the username and Axtm123!# as the password and this command is executed by me:
                                   sudo passwd vi-admin
then type old password that is Axtm123!#  and then new password vmware@123  is configured by me the only message is you will get it is based on the dictionary word but it will accept it. This is what the solution in my lab environment but try this only in your lab environment not in production environment.

Thursday, 23 August 2012

Differences between QuickPrep and Sysprep


This article discusses the main between VMware QuickPrep and Microsoft Sysprep. It further describes the functions of the two methods allowing users to select the appropriate method for creating Linked Clone Desktops.


QuickPrep is a VMware system tool executed by View Composer during a linked-clone desktop deployment. QuickPrep personalizes each desktop created from the Master Image. Microsoft Sysprep is a tool to deploy the configured operating system installation from a base image. The desktop can then be customized based on an answer script. Sysprep can modify a larger number of configurable parameters than QuickPrep.
During the initial startup of each new desktop, QuickPrep:
  • Creates a new computer account in Active Directory for each desktop.
  • Gives the linked-clone desktop a new name.
  • Joins the desktop to the appropriate domain.
  • Optionally, mounts a new volume that contains the user profile information.
This table lists the main differences between QuickPrep and Sysprep:
Removing local accountsNoYes
Changing Security Identifiers (SID)NoYes
Removing parent from domainNoYes
Changing computer nameYesYes
Joining the new instance to the domainYesYes
Generating new SIDNoYes
Language, regional settings, date, and time customizationNoYes
Number of reboots01 (seal & mini-setup)
Requires configuration file and Sysprep  NoYes
Note: A Guest Customization script is required in vCenter Server to use Sysprep. Sysprep is bundled in with Windows 7. For Windows XP, an appropriate Sysprep program needs to be installed on the vCenter Sever.

See Sysprep file locations and versions (1005593) for information on installing Sysprep tools.
For more information on the use of Sysprep and the Guest Customisation wizard,see Customizing Guest Operating Systems andInstalling the Microsoft Sysprep Tools in the vSphere Virtual Machine Administration Guide.


Wednesday, 22 August 2012

Understanding virtual machine snapshots in VMware ESXi and ESX


This article may be helpful when you encounter these issues:
  • Virtual machines are not responding or cannot start due to broken parent and child virtual disk dependencies.
  • Virtual machines are not responding or do not start due to redo logs residing on datastores that do not have free space.
  • Snapshot creation takes too long when specifying the memory snapshot option.
  • Snapshot delete or remove operations result in the vSphere or VMware Infrastructure (VI) Client timing out.
  • Backups fail while quiescing during a snapshot operation.


This article provides information about virtual machine snapshots.



What is a snapshot?

A snapshot preserves the state and data of a virtual machine at a specific point in time.
  • The state includes the virtual machine’s power state (for example, powered-on, powered-off, suspended).
  • The data includes all of the files that make up the virtual machine. This includes disks, memory, and other devices, such as virtual network interface cards.
A virtual machine provides several operations for creating and managing snapshots and snapshot chains. These operations let you create snapshots, revert to any snapshot in the chain, and remove snapshots. You can create extensive snapshot trees.

In VMware Infrastructure 3 and vSphere 4.x, the virtual machine snapshot delete operation combines the consolidation of the data and the deletion of the file. This caused issues when the snapshot files are removed from the Snapshot Manager, but the consolidation failed. This left the VM still running on snapshots, and the user may not notice until the datastore is full.

In vSphere 4.x, an alarm can be created to indicate if a virtual machine was running in snapshot mode. For more information, seeConfiguring VMware vCenter Server to send alarms when virtual machines are running from snapshots (1018029).

In vSphere 5.0, enhancements have been made to the snapshot removal. In vSphere 5.0, you are informed via the UI if the consolidation part of a RemoveSnapshot or RemoveAllSnapshots operation has failed. A new option, Consolidate, is available via the Snapshot menu to restart the consolidation.

Creating a snapshot

When creating a snapshot, there are several options you can specify:
  • Name: This is used to identify the snapshot.
  • Description: This is used to describe the snapshot.
  • Memory: If the <memory> flag is 1 or true, a dump of the internal state of the virtual machine is included in the snapshot. Memory snapshots take longer to create.
  • Quiesce: If the <quiesce> flag is 1 or true, and the virtual machine is powered on when the snapshot is taken, VMware Tools is used to quiesce the file system in the virtual machine. Quiescing a file system is a process of bringing the on-disk data of a physical or virtual computer into a state suitable for backups. This process might include such operations as flushing dirty buffers from the operating system's in-memory cache to disk, or other higher-level application-specific tasks. 

    Note: Quiescing indicates pausing or altering the state of running processes on a computer, particularly those that might modify information stored on disk during a backup, to guarantee a consistent and usable backup.
When a snapshot is created, it is comprised of these files:
  • <vm>-<number>.vmdk and <vm>-<number>-delta.vmdk
    A collection of .vmdk and -delta.vmdk files for each virtual disk is connected to the virtual machine at the time of the snapshot. These files can be referred to as child disks, redo logs, or delta links. These child disks can later be considered parent disks for future child disks. From the original parent disk, each child constitutes a redo log pointing back from the present state of the virtual disk, one step at a time, to the original.

    Note: The <number> value may not be consistent across all child disks from the same snapshot. The file names are chosen based on filename availability.
  • <vm>.vmsd
    The .vmsd file is a database of the virtual machine's snapshot information and the primary source of information for the snapshot manager. The file contains line entries which define the relationships between snapshots as well as the child disks for each snapshot.
  • <vm>Snapshot<number>.vmsn
    These files are the memory state at the time of the snapshot.
Note: The above files will be placed in the working directory by default in ESX/ESX 3.x and 4.x. This behavior can be changed if desired. For more information on creating snapshots in another directory, see Creating snapshots in a different location than default virtual machine directory (1002929). In ESXi 5.x and later snapshots descriptor and delta VMDK files will be stored in the same location as the virtual disks (which can be in a different directory to the working directory). To change this behavior, seeChanging the location of snapshot delta files for virtual machines in ESXi 5.0 (2007563)

What products use the snapshot feature?

In addition to being able to use snapshot manager to create snapshots, snapshots are used by many VMware and third-party products and features. Some VMware products that use snapshots extensively are:
  • VMware Data Recovery
  • VMware Lab Manager
  • VMware vCenter and the VMware Infrastructure Client (Snapshot Manager, Storage vMotion)
Note: This is not an exhaustive list.

How do snapshots work?

Our VMware API allows VMware and third-party products to perform operations with virtual machines and their snapshots. This is a list of common operations that can be performed on virtual machines and snapshots using our API:
  • CreateSnapshot: Creates a new snapshot of a virtual machine. As a side effect, this updates the current snapshot.
  • RemoveSnapshot: Removes a snapshot and deletes any associated storage.
  • RemoveAllSnapshots: Remove all snapshots associated with a virtual machine. If a virtual machine does not have any snapshots, then this operation simply returns successfully.
  • RevertToSnapshot: Changes the execution state of a virtual machine to the state of this snapshot.
  • (vSphere 5.0 only) Consolidate: Merges the hierarchy of redo logs.
This is a high-level overview of how to create, remove, or revert snapshot requests that are processed within the VMware environment:
  1. A request to create, remove, or revert a snapshot for a virtual machine is sent from the client to the server using the VMware API. 
  2. The request is forwarded to the VMware ESX host that is currently hosting the virtual machine in question.

    Note: This only occurs if the original request was sent to a different server, such as vCenter, which is managing the ESX host.
  3. If the snapshot includes the memory option, the ESX host writes the memory of the virtual machine to disk.

    Note: The virtual machine is stunned throughout the duration of time the memory is being written. The length of time of the stun cannot be pre-calculated, and is dependent on the performance of the disk in question and the amount of memory being written. ESX/ESXi 4.x and later have shorter stun times when memory is being written. For more information, seeTaking a snapshot with virtual machine memory stuns the virtual machine while the memory is written to disk (1013163).
  4. If the snapshot includes the quiesce option, the ESX host requests the guest operating system to quiesce the disks via VMware Tools.

    Note: Depending on the guest operating system, the quiescing operation can be done by the sync driver, the vmsync module, or Microsoft's Volume Shadow Copy (VSS) service. For more information on quiescing, see Troubleshooting Volume Shadow Copy (VSS) quiesce related issues (1007696) for VSS or A virtual machine can freeze under load when you take quiesced snapshots or use custom quiescing scripts (5962168) for the SYNC driver.
  5. The ESX host makes the appropriate changes to the virtual machine's snapshot database (.vmsd file) and the changes are reflected in the snapshot manager of the virtual machine.

    Note: When removing a snapshot, the snapshot entity in the snapshot manager is removed before the changes are made to the child disks. The snapshot manager does not contain any snapshot entries while the virtual machine continues to run from the child disk. For more information, see Committing snapshots when there are no snapshot entries in the snapshot manager (1002310).
  6. The ESX host calls a function similar to the Virtual Disk API functions to make changes to the child disks (-delta.vmdkand .vmdk files) and the disk chain.

    Note: During a snapshot removal, if the child disks are large in size, the operation may take a long time. This can result in a timeout error message from either VirtualCenter or the VMware Infrastructure Client. For more information about timeout error messages, see vCenter operation times out with the error: Operation failed since another task is in progress (1004790).

The child disk

The child disk, which is created with a snapshot, is a sparse disk. Sparse disks employ the copy-on-write (COW) mechanism, in which the virtual disk contains no data in places, until copied there by a write. This optimization saves storage space. The grain is the unit of measure in which the sparse disk uses the copy-on-write mechanism. Each grain is a block of sectors containing virtual disk data. The default size is 128 sectors or 64KB.

Child disks and disk usage

It is important to note these points regarding the space utilization of child disks:
  • If a virtual machine is running off of a snapshot, it is making changes to a child or sparse disk. The more write operations made to this disk, the larger it grows.
  • The space requirements of the child disk are in addition to the parent disk on which it depends. If a virtual machine has a 10 GB disk with a child disk, the space used will be 10 GB + the child disk size.
  • Child disks have been known to grow large enough to fill an entire datastore.
  • The speed at which child disks grow is directly dependent on the amount of I/O being done to the disk.
  • The size of the child disk has a direct impact on the length of time it takes to delete the snapshot associated to the child disk.
These Knowledge Base articles touch on the topic of child disks and disk usage:

The disk chain

Generally, when you create a snapshot for the first time, the first child disk is created from the parent disk. Successive snapshots generate new child disks from the last child disk on the chain. The relationship can change if you have multiple branches in the snapshot chain.
This diagram is an example of a snapshot chain. Each square represents a block of data or a grain as described above:
Caution: Manually manipulating the individual child disks or any of the snapshot configuration files may compromise the disk chain. VMware does not recommend manually modifying the disk chain as it may result in data loss. For more information, seeConsolidating snapshots (1007849).

Additional Information

  • To determine if a virtual machine is running on snapshots, see Determining if a virtual machine is using snapshots (1004343). 
  • There are specific considerations when hosting a Microsoft Active Directory controller in a virtual environment. For a full list of considerations, see Microsoft Knowledge Base article 888794.

    Note: The preceding link was valid as of August 1, 2012. If you find the link to be broken, provide feedback on the article and a VMware employee will update the article as necessary.
  • Time-sensitive applications may be impacted by reverting to a previous snapshot. Reverting the snapshot will revert the virtual machine to the point in time when the snapshot was created. This includes any operations conducted by the time-sensitive service or application in the guest operating system. 
  • Reverting virtual machines to a snapshot causes all settings configured in the guest operating system since that snapshot to be reverted. The configuration which is reverted includes, but is not limited to, previous IP addresses, DNS names, UUIDs, guest OS patch versions, etc.

See Also


Growing a local datastore from the command line in vSphere ESXi 4.x and 5.0


VMFS Datastores in vSphere 4.x and 5.0 can be increased in size by adding a new extent on a different storage device (spanning), or by increasing the size of the existing storage device and then growing the existing datastore extent to fill that available adjacent capacity.
VMFS Datastore extents may be contained within Primary or Logical partitions, following the MBR/EBR partitioning scheme. VMFS Datastores on the ESX boot device are contained within a Logical partition, and those on an ESXi boot device are contained within a Primary partition.
  • Datastore extents within a Primary partition and on a non-Local storage device can be grown into adjacent space using the vSphere Client. For more information, see the Changing VMFS Datastore Properties section of the ESX/ESXi Server Configuration Guide for your version of vSphere.
  • Datastore extents within Extended and Logical partitions on a Local or Boot storage device cannot be grown into adjacent space using the vSphere Client. This is the default layout for an ESX 4.x installation. For more information, see Growing a local datastore from the command line in vSphere ESX 4.x (1009125).
  • Datastore extents within Primary partitions on a Local or Boot storage device cannot be grown into adjacent space using the vSphere Client. This is the default layout for an ESXi 4.x and 5.0 installation. This article provides steps for growing an existing VMFS Datastore in a Primary partition to fill available adjacent space on the local boot device.
  1. This article assumes that the underlying storage volume has already had its capacity increased from the hardware perspective, possibly by adding additional disk to a RAID set. For more information, engage your hardware vendor.
  2. A Datastore on a LUN detected as a snapshot cannot be grown. For more information, see vSphere handling of LUNs detected as snapshot (1011387).
  3. A Datastore's partitions can only be grown into contiguous adjacent space on the disk. Ensure that the partitions in question are at the end of the disk.
Warning: Be very careful to not overlap the any Primary and Logical partitions. This could result in data loss.


To increase the size of a Datastore on a local boot storage device, recreate the partition layout to accommodate the larger filesystem, and then grow the Datastore to fill the larger partition.
  1. Use the boot device hardware's management tools to add additional disk capacity to the device. For more information, engage your hardware vendor.
  2. Open a console to the ESXi host. For more information, see   Using Tech Support Mode in ESXi 4.1 and ESXi 5.0 (1017910)
  3. Obtain the device identifier for the Datastore to be modified (eg: naa, mpx, eui, vml, etc). For more information, seeIdentifying disks when working with VMware ESX (1014953).

    # vmkfstools -P "/vmfs/volumes/DatastoreName

    Example output:

    VMFS-3.33 file system spanning 1 partitions.
    File system label (if any): DatastoreName
    Mode: public
    Capacity 145223581696 (138496 file blocks * 1048576), 43937431552 (41902 blocks) avail
    UUID: 4a14d968-88bf7161-700f-00145ef48f76
    Partitions spanned (on "lvm"):

  4. Record the amount of free disk space on the Datastore. For more information, see Investigating disk space on an ESX or ESXi host (1003564).
  5. Equipped with the device identifier, identify the existing partitions on the device using the partedUtil command. For more information, see Using the partedUtil command line utility on ESX and ESXi (1036609).

    # partedUtil get "/vmfs/devices/disks/mpx.vmhba0:C0:T0:L0"

    For example, a disk containing an ESX 4.x installation with 8 existing partitions:

    15360 64 32 40000001 - Geometry of the disk. Disk size in sectors is 40000001.
    4 32 8191 4 128 - Primary #4, Type 4=Fat16<32MB, Bootable, Sectors 32-8191
    1 8192 1843199 5 0 - Primary #1, Type 5=Extended, Sectors 
    5 8223 520191 6 0 - Logical #5, Type 6=Fat16, Sectors 
    6 520224 1032191 6 0 - Logical #6, Type 6=Fat16, Sectors 
    520224-10321917 1032224 1257471 252 0 - Logical #7, Type 252=0xFC=VMKcore, Sectors 1032224-1257471
    8 1257504 1843119 6 0 - Logical #8, Type
     6=Fat16, Sectors 1257504-1843119
    2 1843200 10229759 6 0 - Primary #2, Type 6=Fat16, Sectors 
    3 10229760 31457279 251 0 - Primary #3, Type 251=0xFB=VMFS, Sectors 
    | |        |        |   |
    | |        |        |   \--- attribute
    | |        |        \------- type
    | |        \---------------- ending sector
    | \------------------------- starting sector
    \--------------------------- partition number

  6. Identify the partitions which need to be resized, and the size of the space to be used. From the example in step 5, Primary Partition 3 is the last partition on the disk, and there is empty free space between this partition and the end of the disk. For example:


    Logical #5
    Type 6
    Logical #6
    Type 6
    Logical #7
    Type 252
    Logical #8
    Type 6


    Partition 4
    Partition 1
    Type 5 (Extended)
    Primary #2
    Type 6
    Primary #3
    Type 251
    Empty Space
    To Be Used
  7. Identify the desired ending sector number for the target VMFS Datastore's partitions. To use all space out to the end of the disk, subtract 1 from the disk size in sectors as reported in step 5 to obtain the last usable sector.

    For example, Disk sector count 40000001 - 1 = 40000000 as the last usable sector.

    Note: With ESXi 5.0 we can use the partedUtil getUsableSectors option to get the last usable sector.

    # partedUtil getUsableSectors "/vmfs/devices/disks/mpx.vmhba0:C0:T0:L0"
  8. Resize the partition containing the target VMFS Datastore using the partedUtil command, specifying the existing starting sector of the partition and the desired ending sector:

    # partedUtil resize "/vmfs/devices/disks/Device" PartitionNumber NewStartingSector NewEndingSector

    For example, to resize the Primary partition 3 from the example in step 5:

    # partedUtil resize "/vmfs/devices/disks/mpx.vmhba0:C0:T0:L0" 3 10229760 40000000
  9. During step 8, the partedUtil command may report the warning:

    The kernel was unable to re-read the partition table on /dev/Device (Device or resource busy).

    If you receive this warning, reboot the host before proceeding with the next step. For more information, see Rebooting an ESX Server host (1003530).
  10. The partition tables have been adjusted, but the VMFS Datastore within the partition is still the same size. There is now empty space within the partition in which the VMFS Datastore can be grown. For example:


    Logical #5
    Type 6
    Logical #6
    Type 6
    Logical #7
    Type 252
    Logical #8
    Type 6

    DatastoreEmpty Space
    Partition 4
    Partition 1
    Type 5 (Extended)
    Primary #2
    Type 6
    Primary #3
    Type 251
  11. Grow the VMFS Datastore in to the new space using the vmkfstools --growfs command, specifying the partition containing the target VMFS Datastore twice.

    # vmkfstools --growfs "/vmfs/devices/disks/device:partition" "/vmfs/devices/disks/device:partition"

    For example:

    # vmkfstools --growfs "/vmfs/devices/disks/mpx.vmhba0:C0:T0:L0:3" "/vmfs/devices/disks/mpx.vmhba0:C0:T0:L0:3"
  12. Validate that the size of the VMFS Datastore has increased. For more information, see Investigating disk space on an ESX or ESXi host (1003564).

    Note: Click the Refresh button in the vSphere Client to update the Datastore capacity and usage.

See Also