VMware vSphere storage virtualization is a combination of vSphere features and APIs that provide an abstraction layer for physical storage resources to be addressed, managed and optimized in a virtualization deployment.

Storage virtualization technology provides a fundamentally better way to manage storage resources for your virtual infrastructure, giving your organization the ability to:

  • Improve storage resource utilization and flexibility significantly.
  • Simplify operating system patching and driver requirements regardless of storage topology.
  • Increase application uptime and simplify day to day operations.
  • Leverage and complement your existing storage infrastructure.

About Storage

Storage in a Non-Virtualized Environment

In a non-virtualized environment, servers connect directly to storage, either internal to the server chassis or in an external array. The biggest downside is that a specific server expects complete ownership of the physical device, with an entire disk drive tied to a single server. Sharing storage resources in a non-virtualized environment requires complex file systems or moving away from block-based storage to file-based network-attached storage (NAS).

Physical Architecture Storage Diagram

Physical Architecture Storage Diagram

Datastores and Virtual Machines

A virtual machine is stored as a set of files in its own directory in a datastore, which is a logical container, like a file system, that hides the specifics of each storage device and provides a uniform model for storing virtual machine files. Datastores can also be used for storing ISO images, virtual machine templates and floppy images. They can be backed by either a Virtual Machine File System (VMFS) or a Network File System (NFS), depending on the type of storage. A VMFS datastore can be deployed on a SCSI-based local or networked storage device, while an NFS datastore can be deployed on a NAS device.

Virtual Machine Datastores Diagram

Virtual Machine Datastores Diagram

VMware Virtual Machine File System

VMware vSphere VMFS allows multiple vSphere servers to access shared virtual machine storage concurrently and enables virtualization-based distributed architecture services to operate across a cluster of vSphere servers. It provides the foundation for scaling virtualization beyond the boundaries of a single system.

vSphere supports all common storage interconnects for block-based storage, including direct-attached storage, Fibre Channel, FCoE (Fibre Channel over Ethernet) and iSCSI. vSphere also supports placing datastores on NAS storage, accessed via an IP network.

VMware Virtual Machine File System (VMFS)

VMware Virtual Machine File System (VMFS)

Guest OS View of Storage

vSphere greatly simplifies accessing storage from the guest operating system. The virtual hardware presented to a vSphere guest operating system includes a set of common SCSI and IDE controllers, so the guest operating system sees a simple physical disk attached via a standard controller. Presenting a virtualized view of storage to the guest operating system has several advantages, including easier storage management, expanded support and access, and improved efficiency.


Storage Distributed Resources Scheduler (DRS)

Provides intelligent virtual machine placement and load balancing mechanisms based on I/O latency and storage capacity.

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Profile-Driven Storage

Reduces the number of storage resource selection steps by grouping storage according to user-defined policies.

Read More About Profile-Driven Storage

Storage vMotion

Performs proactive, non-disruptive storage migrations, eliminating virtual machine storage I/O bottlenecks and freeing up valuable storage capacity.

Read More About Storage vMotion

Storage I/O Control

Prioritizes storage access by continuously monitoring the I/O load of a storage volume and dynamically allocating available I/O resources to virtual machines according to business needs.

Read More About Storage I/O Control

Virtual Machine File System (VMFS)

Allows multiple vSphere hosts to read and write to the same storage concurrently and supports all common storage interconnects for block-based storage (DASD, Fibre Channel, FCoE, iSCSI and NAS).

Read More About Virtual Machine File System

Storage Thin Provisioning

Increases virtual machine storage utilization by enabling dynamic allocation and intelligent provisioning of physical storage capacity.

Read More About Storage Thin Provisioning

Storage APIs

Enhances your storage awareness, data protection and array integration and takes advantage of multi-pathing capabilities offered by third-party storage vendors.

Read More About Storage APIs

vSphere Flash Read Cache

Virtualizes server-side flash, providing a high performance read cache layer that dramatically lowers application latency. The caching is fully transparent to the VM without requiring any guest agents.

Read more about Flash Read Cache