Configure Virtual Hard Disks in VMware Player
Learn how VMware Player virtual hard disks work, including VMDK files, controllers, capacity, allocation, split files, and adding data disks.
A VMware virtual hard disk is a software-defined storage device attached to a virtual machine. The guest operating system treats it like a physical disk, while the host operating system stores its contents in one or more virtual disk files.
This guide explains how to select a disk controller, plan capacity, choose growable or preallocated storage, select a single-file or split-file layout, and add a new disk through VMware Player settings.
What a VMware virtual hard disk does
The virtual hard disk provides persistent storage for the guest. It holds the guest operating system, installed applications, configuration files, and user data. Data remains available after the virtual machine is powered off, just as data on a physical disk remains available after a computer shuts down.
The guest sees a disk through a virtual controller such as IDE, SATA, or SCSI. The host does not normally see that disk as a separate physical device. Instead, VMware Player reads and writes VMDK files on a host storage volume. The guest-visible disk interface and the host's physical storage interface are separate layers.
- Guest layer: the guest detects a virtual IDE, SATA, or SCSI disk and uses its own disk drivers.
- Virtualization layer: VMware Player translates guest disk operations.
- Host layer: the VMDK contents are stored on a host device such as an internal disk, SSD, or other fast-access storage media.
Consequently, a guest can use a virtual SCSI disk even when its VMDK files are stored on a host SATA device. Conversely, a guest-visible IDE disk can be backed by files on fast host storage. For performance, plan around the host device's speed, latency, capacity, and available free space.
VMDK files, names, and locations
VMDK is VMware's virtual disk file format. A typical virtual disk name is based on the virtual machine name, such as Linux-Test.vmdk. VMware Player may also use related descriptor or extent files, depending on the selected disk layout.
Keep the virtual disk files with the virtual machine's configuration and other related files unless you intentionally manage the paths and references. When moving or copying a virtual machine, include every file required by its virtual disks. The virtual machine files topic provides related file-management context.
A VMDK file name is not the same as the disk label shown inside the guest. For example, the host might store Linux-Test.vmdk, while the guest labels a partition Projects. Renaming a guest volume does not necessarily rename the VMDK, and renaming host-side files manually can break references.
Choose a virtual disk controller
A virtual disk controller is the interface through which the guest accesses a virtual disk. Select a controller that the guest operating system supports, especially when the disk will contain the guest's boot files. A controller that VMware Player can configure is not automatically usable by every guest.
| Controller type | Guest-visible interface | Guest driver consideration | Typical selection guidance |
|---|---|---|---|
| IDE | IDE disk | Generally use a guest with IDE storage support. | Choose when broad compatibility with an older or simple guest configuration is more important than using another interface. |
| SATA | SATA disk | The guest must support its virtual SATA controller and disk driver. | Choose for a guest that is known to support SATA and is configured to use it. |
| SCSI with LSI Logic | SCSI disk | The guest needs an appropriate LSI Logic SCSI driver. | Use when the guest operating system supports the LSI Logic adapter. |
| SCSI with BusLogic | SCSI disk | The guest needs an appropriate BusLogic SCSI driver. | Use when the guest operating system supports the BusLogic adapter. |
For a boot disk, the guest must have its controller driver available early enough in startup to access the system volume. If the driver is missing or the adapter type is unsupported, the guest may fail to boot or may not detect the disk. For a non-boot disk, you may be able to install or enable a driver after startup, but compatibility should still be confirmed first.
Plan virtual disk capacity
Set the maximum capacity according to the guest operating system's requirements, the applications you will install, current data, and anticipated growth. Leave room for updates, temporary files, logs, caches, and working space.
IDE and SCSI virtual disks have maximum supported capacities determined by the VMware Player version, virtual hardware configuration, disk type, and guest limitations. Check the capacity limits applicable to your installation before creating a very large disk. The guest operating system may impose additional partition, file-system, or boot limitations.
Do not confuse configured capacity with host space currently consumed:
- Configured maximum capacity is the largest disk size presented to the guest.
- Host consumption is the amount of storage currently occupied by the VMDK files and can be smaller for a growable disk.
- A growable disk can eventually consume storage approaching its configured capacity as the guest writes data.
Growable and preallocated disks
A growable disk starts with relatively low host-space consumption and expands as the guest writes data, up to the configured maximum. This is commonly useful for a small test virtual machine because unused guest capacity does not immediately occupy the entire host volume.
A preallocated disk reserves the configured capacity on the host when the disk is created. Creation can take longer, and the full amount of host storage must be available immediately. In return, capacity is reserved in advance, which can make storage planning more predictable for a known workload.
| Option | How host space is used | Primary benefit | Primary trade-off | Best-fit scenario |
|---|---|---|---|---|
| Growable disk | Increases as the guest writes data. | Uses less host space at first. | The host volume must keep enough free space as the disk grows. | Small Linux test machines and variable workloads. |
| Preallocated disk | Reserves the full configured capacity at creation. | Provides predictable reserved capacity. | Requires the full capacity immediately and may take longer to create. | Known workloads where the host can reserve the required space. |
| Single-file disk | Stores the virtual disk in one file, subject to destination file-system limits. | Simpler copying and file management. | A destination with a low maximum file size may reject the file. | Modern host file systems without restrictive per-file limits. |
| Split disk with 2 GB extent files | Stores the disk across multiple extent files, each limited to 2 GB. | Works around older file systems with small maximum-file-size limits. | More files must be copied, tracked, and kept together. | Transfers to legacy file systems or destinations with a 2 GB per-file restriction. |
Before creating a growable disk, confirm that the host volume can accommodate its possible growth. Monitor host free space while the virtual machine is running. A growable disk does not bypass the host's capacity limit.
Single-file and split-file layouts
A single-file virtual disk stores the disk in one file. This is straightforward to move, back up, and identify, provided the destination file system supports the file's size.
A split virtual disk stores the disk in multiple disk extents. Each extent is limited to 2 GB. The collection of extents represents one virtual disk; the files are not independent disks that can be used separately.
Use the split layout when a destination file system has a maximum file size that is lower than the VMDK's total size. The layout can also make individual files easier to handle in environments with file-size restrictions, but it increases file-management overhead.
Add a new virtual hard disk
- Shut down the virtual machine. Do not change virtual hardware while the machine is running unless the VMware Player interface explicitly supports that operation for the device.
- Open the virtual machine's settings.
- Use the add-hardware workflow and choose to add a hard disk.
- Choose whether to create a new virtual disk or use an existing VMDK. Use the existing-disk option when the disk has already been created and all required files are available.
- Select a controller type supported by the guest operating system. Confirm SCSI adapter compatibility if choosing LSI Logic or BusLogic.
- Set the maximum capacity based on the guest's storage needs and expected growth.
- Choose growable or preallocated allocation.
- When offered, choose a single virtual disk file or split files limited to 2 GB. Select split files when the destination file system requires that compatibility.
- Finish the wizard, review the hardware settings, and start the virtual machine.
For a newly added non-boot disk, VMware Player's attachment is only the first step. Inside the guest, use its disk-management tools to detect or rescan the device, initialize it if required, create a partition or volume, format it with an appropriate file system, and mount or assign it a drive letter. The disk is not ready for normal data storage until these guest-side steps are complete.
For a detailed task-specific workflow, see adding a new virtual hard disk. If the disk already exists, see adding an existing virtual hard disk.
Practical configurations
Small Linux test machine
Create a new VMDK with a modest maximum capacity. Choose growable allocation so the host initially uses only the storage required by the guest's actual contents. Select IDE, SATA, or a supported SCSI adapter according to the Linux guest's configured drivers rather than selecting solely by the host's physical disk type.
Transfer to a legacy file system
Choose the split-file layout with 2 GB extent files. When transferring the virtual machine, copy the descriptor and every extent together, preserving the names and directory relationship required by the disk.
Separate data disk
Add a new disk through virtual machine hardware settings, select a guest-supported controller, and choose capacity and allocation based on the workload. After startup, initialize, partition, format, and mount the disk inside the guest before writing data to it.
Known workload requiring reserved storage
Create a preallocated disk when the full capacity must be reserved from the beginning. Check the host volume's free space before creation and account for the guest's other files and future virtual machines.
Troubleshooting
The guest does not detect a newly attached SCSI disk
The guest may lack a driver for the selected SCSI adapter, or the adapter type may not be supported. Verify whether the guest supports LSI Logic or BusLogic, install the required driver when appropriate, or attach the disk through a controller supported by the guest.
The host volume runs out of free space
A growable VMDK may have expanded as the guest wrote data. Configured guest capacity is not the same as currently consumed host space, but the host must be able to accommodate future growth. Free or add host storage, monitor free space, and use preallocation only when the required capacity can be reserved safely.
A virtual disk cannot be copied to a destination volume
The destination file system may have a maximum file size below the size of a single VMDK file. Create or convert the disk using the split layout with 2 GB extent files when targeting that type of destination.
A moved split disk no longer opens
One or more extent files may have been omitted, renamed, or separated from the other disk files. Restore the descriptor and all extent files to the expected location with their expected names, then attach the disk again.
The disk is visible in VMware Player but unavailable in the guest
The guest may not yet have initialized, partitioned, formatted, or mounted the device. Use the guest operating system's disk-management tools to complete those steps. Also check that the guest has detected the selected controller and disk.
Exam-relevant notes
- A VMDK is a host-side representation of a virtual hard disk.
- The guest operating system, not the host's physical storage interface, determines whether a virtual IDE, SATA, or SCSI disk can be used.
- LSI Logic and BusLogic are SCSI adapter choices; the guest requires compatible drivers.
- A growable disk consumes host space as data is written, while a preallocated disk reserves its configured capacity at creation.
- A split disk consists of multiple 2 GB extent files. Every extent must remain with the disk when it is moved or copied.
- Adding a disk in VMware Player does not automatically initialize, partition, format, or mount it inside the guest.
For broader hardware configuration, see configuring a virtual machine for compatibility and what a virtual disk is.