VMware ESXi and vSphere Cluster Management

Configure Virtual Hard Disks in VMware Player

Learn how VMware Player virtual hard disks use VMDK files, controller types, capacity allocation, provisioning, and single-file or split-file layouts.

A virtual hard disk is a software-defined storage device attached to a virtual machine. It gives the guest operating system persistent storage for its system files, applications, and user data.

The disk seen by the guest is not necessarily a physical disk in the host computer. VMware Player presents a virtual disk device to the guest, while the host operating system stores that device as one or more files on host storage.

How VMware Virtual Disks Are Stored

VMware Player uses the VMDK format for virtual hard disks. VMDK means VMware virtual disk file format. A disk commonly follows a naming pattern based on the virtual machine name, such as <VM-NAME>.vmdk.

A VMDK may be represented by one file or by multiple related files. The number and names of those files depend on the selected storage layout and allocation options. Treat all files belonging to a disk as one unit when copying, backing up, or moving the virtual machine.

Virtual Disk Controllers

A virtual disk controller is the interface through which the guest operating system accesses a virtual disk. VMware Player can present IDE, SATA, or SCSI controller types to the guest. This virtual interface is separate from the interface used by the host computer's physical storage.

Controller type	Guest compatibility consideration	Driver requirement	Key note
IDE	Often useful for guests with broad legacy storage support.	The guest needs support for the presented IDE device.	The guest sees an IDE device even when the VMDK is stored on modern host storage.
SATA	Use when the guest supports the presented SATA controller.	The guest needs a compatible SATA storage driver.	SATA describes the guest-visible virtual controller, not necessarily the host drive interface.
SCSI	Confirm that the guest supports the selected virtual SCSI adapter.	An appropriate adapter driver may be required, such as LSI Logic or BusLogic.	Useful for supported guests, but an unsupported adapter can prevent disk detection.

For SCSI storage, verify support for the selected adapter type, such as LSI Logic or BusLogic, before attaching the disk. A guest may need an installed or loaded driver before it can use the virtual disk.

Host Storage Independence

The guest-visible controller and the host's physical storage interface do not have to match. An IDE, SATA, or SCSI virtual disk can be stored on suitable fast-access host storage, including host devices connected through IDE, SATA, SCSI, or other high-performance storage technologies.

For example, a guest can use a virtual SCSI disk while the VMDK files reside on a host SATA or other high-performance drive. The controller choice describes how VMware Player presents the disk inside the virtual machine; it does not dictate the physical interface of the host device.

Virtual Disk Capacity

The configured capacity is the maximum virtual capacity reported to the guest. It is not necessarily the amount of host storage consumed when the disk is created.

IDE and SCSI virtual hard disks support capacities up to 8 TB. When planning a large disk, also check the guest operating system, selected controller, guest file system, host file system, and available host storage. A capacity that is technically configurable may still be impractical or unsupported by another part of the storage stack.

Growable and Preallocated Disks

Disk provisioning determines how host storage is reserved. The default growable model starts with relatively small host-side files. As the guest writes data, the files expand until they reach the configured virtual capacity.

A preallocated disk reserves the full configured capacity on the host when the disk is created. This can make initial creation slower and requires enough free host storage immediately, but it provides predictable space reservation.

Option	Initial host space usage	Growth behavior	Advantages	Planning considerations
Growable allocation	Starts smaller than the configured maximum.	Expands as the guest writes data, up to the maximum capacity.	Uses less host space initially and can be created more quickly.	Monitor host free space and plan for future growth.
Preallocated allocation	Reserves the full configured capacity at creation.	Does not need to grow through normal guest writes.	Provides immediate, predictable host-space reservation.	Requires sufficient free space and may take longer to create.

Single-File and Split-File Layouts

A virtual disk can be stored as one large file or split into multiple component files. VMware Player provides a split option that limits each component file to 2 GB.

Layout	Stored as	Best use case	Compatibility consideration
Single virtual disk file	One VMDK file, subject to the selected disk format and configuration.	Hosts with file systems that support large files and situations where simpler file management is preferred.	May not fit on an older file system with a file-size limit below the VMDK's size.
Multiple files split at 2 GB	Several related VMDK component files, each limited to 2 GB.	Moving a disk to older file systems that cannot support files larger than 2 GB.	Every component file must be copied and kept together; losing one component can make the disk unusable.

Splitting can improve compatibility with older file systems, but it increases the number of files that must be managed. When moving a split disk, preserve all related files and their names. Verify that the destination has enough total free space for the complete virtual disk.

Adding and Configuring a New Virtual Hard Disk

Open the target virtual machine's settings in VMware Player.
Add a new hard disk, or select an existing virtual hard disk to review its configuration.
Choose a guest-visible controller type: IDE, SATA, or SCSI where supported.
Set the virtual disk capacity. For IDE and SCSI disks, remain within the supported maximum of 8 TB and check all guest and host limitations.
Choose growable allocation if conserving initial host space is more important than reserving the complete capacity immediately. Choose preallocation when immediate full reservation is required.
Choose a single-file layout when the host file system supports large files. Choose the 2 GB split layout when compatibility with an older file system is needed.
Complete the VMware Player configuration and boot the guest.
Inside the guest, partition and format the new disk, then mount it or assign it a drive letter as appropriate.

Adding a virtual disk does not automatically create a usable guest volume. The guest may need to detect the device, initialize it, create a partition, format the partition with a file system, and mount or assign it before applications can store files on it.

Choosing a Configuration

General-purpose Linux virtual machine

Use a controller supported by the Linux guest. A growable disk is appropriate when reducing initial host storage usage matters more than reserving the entire capacity. Use a single file when the host file system supports large files and the disk does not need to be transferred to an older file system.

Transfer to an older file system

Choose the split-disk option with 2 GB component files. Move every file belonging to the VMDK together, and check the destination's available total capacity before starting the transfer.

Workload with known capacity requirements

Configure the required virtual capacity within the supported limits. Choose preallocation when the host must reserve all required space immediately, and confirm that the host storage location has enough free capacity.

Additional SCSI data disk

Confirm that the guest supports the selected LSI Logic or BusLogic SCSI adapter. Select SCSI during disk configuration. After booting, use the guest's disk-management tools to detect, initialize, partition, and format the additional disk.

Troubleshooting

The guest does not detect a new SCSI disk

Verify that the guest supports the selected virtual SCSI adapter.
Check whether the required LSI Logic or BusLogic driver is installed or loaded.
Confirm that the disk was added to the correct virtual machine.
Use the guest's disk-management tools to rescan and initialize the disk if necessary.

The host runs out of space while a growable disk is in use

The VMDK files expand as the guest writes data.
Compare the configured maximum capacity with the host's available free space.
Free or add host storage, and monitor future growth.
Do not assume that a small initial VMDK file represents the disk's eventual storage requirement.

A disk cannot be copied to an older file system

The disk may contain a file larger than the destination file system permits.
Use a 2 GB split layout when creating or preparing a compatible disk.
Transfer every related split-disk file together.

Preallocated disk creation fails or takes a long time

Confirm that the host has free space equal to the full configured virtual capacity.
Allow additional time for the host to reserve the space.
Choose growable allocation when immediate full reservation is not required.

Exam-Relevant Notes

A virtual hard disk is persistent guest storage, not necessarily a physical disk.
VMDK is VMware's virtual disk file format.
IDE, SATA, and SCSI describe guest-visible virtual controller choices; they do not identify the host's physical storage interface.
SCSI requires suitable guest adapter support, such as an LSI Logic or BusLogic driver where applicable.
IDE and SCSI virtual hard disks support capacities up to 8 TB.
Growable disks expand with guest writes; preallocated disks reserve the full configured capacity at creation.
A 2 GB split layout creates multiple files for compatibility with older file systems, and all component files must remain together.
A newly attached disk may still require guest-side initialization, partitioning, formatting, and mounting.

For a concise configuration checklist, review the virtual hard disk configuration guide while applying these choices to your virtual machine.