What Files Make Up a Virtual Machine?

You may never need to know the file names or locations for your virtual machine files. Virtual machine file management is performed by VMware Workstation. If the behind the scenes file structure is not interesting to you, skip this section.

A virtual machine typically is stored on the host computer in a set of files, usually in a directory created by Workstation for that specific virtual machine.

The key files are listed here by extension. In these examples, <vmname> is the name of your virtual machine

Extension File Name Description
.log <vmname>.log



This is the file that keeps a log of key VMware Workstation activity. This file can be useful in troubleshooting if you encounter problems. This file is stored in the directory that holds the configuration (.vmx) file of the virtual machine.
.nvram <vmname>.nvram



This is the file that stores the state of the virtual machine’s BIOS.
.vmdk <vmname>.vmdk This is a virtual disk file, which stores the contents of the virtual machine’s hard disk drive.

A virtual disk is made up of one or more .vmdk files. If you have specified that the virtual disk should be split into 2GB chunks, the number of .vmdk files depends on the size of the virtual disk. As data is added to a virtual disk, the .vmdk files grow in size, to a maximum of 2GB each. (If you specify that all space should be allocated when you create the disk, these files start at the maximum size and do not grow.) Almost all of a .vmdk file’s content is the virtual machine’s data, with a small portion allotted to virtual machine overhead.

If the virtual machine is connected directly to a physical disk, rather than to a virtual disk, the .vmdk file stores information about the partitions the virtual machine is allowed to access.

Earlier VMware products used the extension .dsk for virtual disk files.

<diskname>-<###>.vmdk This is a redo-log file, created automatically when a virtual machine has one or more snapshots. This file stores changes made to a virtual disk while the virtual machine is running. There may be more than one such file. The ### indicates a unique suffix added automatically by VMware Workstation to avoid duplicate file names.
.vmem <uuid>.vmem The virtual machine’s paging file, which backs up the guest main memory on the host file system. This file exists only when the virtual machine is running, or if the virtual machine has crashed.
<snapshot_name_and_number> Each snapshot of a virtual machine that is powered on has an associated .vmem file, which contains the guest’s main memory, saved as part of the snapshot.
.vmsd <vmname>.vmsd This is a centralized file for storing information and metadata about snapshots.
.vmsn <vmname>-Snapshot.vmsn This is the snapshot state file, which stores the running state of a virtual machine at the time you take that snapshot
<vmname>-Snapshot<###>.vmsn This is the file which stores the state of a snapshot
.vmss <vmname>.vmss This is the suspended state file, which stores the state of a suspended virtual machine

.Some earlier VMware products used the extension .std for suspended state files

.vmtm <vmname>.vmtm This is the configuration file containing team data.
.vmx <vmname>.vmx This is the primary configuration file, which stores settings chosen in the New Virtual Machine Wizard or virtual machine settings editor. If you created the virtual machine under an earlier version of VMware Workstation on a Linux host, this file may have a .cfg extension
.vmxf <vmname>.vmxf This is a supplemental configuration file for virtual machines that are in a team. Note that the .vmxf file remains if a virtual machine is removed from the team.

There can be other files in the directory, some of which are present only while a virtual machine is running.

Source : http://www.vmware.com/support/ws55/doc/ws_learning_files_in_a_vm.html

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