ID #1109

5. The different types of vmdks

VMDKs are used for different purposes:

They can describe a normal virtual disk, a snapshot or a physical disk.

 

 

Regular vmdks

 

Regular vmdks means that this are complete virtual disks that can be used by a VM
or can be mounted by any of the third-party mount-tools.
The description text defines all parameters - including geometry, adapter type and used binary data files.

To recover data you need the text description and all referenced binary files.
 

VMware-name : monolithicSparse
Platform :     WS    
Number of files : 1    
Maximum nominal vmdk-size : 950 Gb or 2040 Gb
Maximum file-size : 2Gb
Extension of descriptor : embedded
Extension used for data : *.vmdk
Description: This is a one-piece growing disk in one piece with an embedded description


VMware-name : monolithicFlat
Platform :     WS    
Number of files : 2   
Maximum nominal vmdk-size : 950 Gb or 2040 Gb
Maximum file-size : 950Gb or 2 Tb
Extension of descriptor : *.vmdk
Extension used for data : *-flat.vmdk
Description: This is a one-piece pre-allocated disk with an externall description


VMware-name : twoGbMaxExtentSparse < 950 Gb
Platform :     WS    
Number of files : 2    - 477
Maximum nominal vmdk-size : < 950 Gb
Maximum file-size : 2Gb
Extension of descriptor : *.vmdk
Extension used for data : *-s00*.vmdk
Description: This is a growing disk split into 2Gb chunks with an externall description


VMware-name : twoGbMaxExtentSparse larger then 950 Gb upto 2040 Gb
Platform :     WS 7
Number of files : 2
Maximum nominal vmdk-size : 2040 Gb
Maximum file-size : 2040 Gb
Extension of descriptor : *.vmdk
Extension used for data : *-s001.vmdk
Description: This is a one-piece growing disk with external descriptor-file
   

VMware-name : twoGbMaxExtentFlat < 950 Gb
Platform :     WS    
Number of files : 2    - 477
Maximum nominal vmdk-size : < 950 Gb
Maximum file-size : 2Gb
Extension of descriptor : *.vmdk
Extension used for data : *-f00*.vmdk
Description: This is a preallocated disk split into 2Gb chunks with external descriptor-file
   

VMware-name : vmfs
Platform :     ESX   
Number of files : 2   
Maximum nominal vmdk-size : depends on blocksize used to format the VMFS-filesystem
Maximum file-size : 2040 Gb
Extension of descriptor : *.vmdk
Extension used for data : *-flat.vmdk
Description: This is a preallocated disk  with external descriptor-file

 


Snapshots or Redologs


Snapshots - I prefer to call them REDOlogs - can be stored in this 3 different formats.
You can mix different formats in one snapshot-chain but this is NOT recommended !
Usually you let VMware decide which format to use for the REDOlogs.

The description text of a snapshot does not define the disk geometry.
Instead it has a pointer to its parent-disk.

Snapshots can be expanded but this is not recommended - only use in emergencies.

The content of a snapshot vmdk can not be analysed directly.
To read data from a snapshot vmdk it must be attached to a parent disk.



VMware-name : monolithicSparse
Platform :     WS    
Number of files : 1
Maximum nominal vmdk-size : inheritated from parent vmdk
Maximum file-size :
Extension of descriptor : embedded
Extension used for data : *.vmdk
Description: This is a one piece snapshot with embedded description


VMware-name : twoGbMaxExtentSparse
Platform :     WS    
Number of files : 2 - 477
Maximum nominal vmdk-size : inheritated from parent vmdk
Maximum file-size : max 2Gb per single chunk
Extension of descriptor : *-00000*.vmdk
Extension used for data : *-00000*-s00*.vmdk
Description: This is a snapshot split into 2 Gb chunks with embedded description


VMware-name : vmfsSparse
Platform :     ESX
Number of files : 2
Maximum nominal vmdk-size : inheritated from parent vmdk
Maximum file-size : depends on blocksize
Extension of descriptor : *-00000*.vmdk
Extension used for data :*-00000*-delta.vmdk
Description: This is a one piece snapshot with external description


Tags: types, vmdk

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