VMware vSphere ^TM

Control your storage costs by eliminating storage waste and the need for dedicated storage capacity. vSphere Storage Thin Provisioning, a key component of vSphere’s storage capabilities, allows over-allocation of storage capacity for increased storage utilization, enhanced application uptime and simplified storage capacity management.

• Increase storage utilization
• Decrease downtime and improve reliability for better business continuity and disaster recovery
• Simplify storage capacity management

Increase Storage Utilization

Eliminate the need to dedicate full capacity upfront while providing vSphere administrators with the capacity they need for future growth.

• Allow administrators to dedicate more capacity to virtual machines than they have
• Eliminate the cost of unused over-allocated storage
• Save resources and space by reducing your physical storage needs

Enhance Application Uptime for Improved Business Continuity

Let storage administrators do their jobs without the need for extensive coordination between application owners and virtual machine owners.

• Increase the uptime of applications by not having to take them offline as often for maintenance
• Lessen the need for time-consuming cross-team coordination

Simplify Storage Capacity Management

Eliminate manual processes and streamline storage capacity management.

• Safely manage storage capacity without complex coordination between different administrators
• Set alarms and alerts to safely thin provision storage to virtual machines

VMware vSphere Thin Provisioning is included in all VMware vSphere editions and kits.

Increased Storage Utilization for Virtual Machines

VMware vSphere Storage Thin Provisioning dramatically increases virtual machine storage utilization by enabling dynamic allocation and intelligent provisioning of physical storage capacity.

Storage Thin Provisioning gives you higher utilization by letting you dedicate more storage capacity than the actual available capacity. Traditionally, application administrators estimated and requested capacity, keeping future growth in prospective. This over-provisioning of capacity resulted in unused space, similar to the problem of RAM over-commitment in the server space. 



With Storage Thin Provisioning operating at the virtual disk level, vSphere administrators can allocate virtual disk files as “thick” or “thin” format. Thin provisioning of virtual disks allows virtual machines on vSphere hosts to provision the entire space required for the disk’s current and future activities, but at first commits only as much storage space as needed to store data. It cuts out the space allocated but not used and grows as more data is stored in the virtual disk.

Thin Provisioning enables you to over commit the datastores and in doing so increase the storage utilization by cutting down the amount of space that is allocated but not used. VMware vCenter Server provides the visibility of space allocations and space used, and issues alerts and alarms to inform the vSphere admin of a pending out of space condition or excessive over-commitment percentages.



vSphere Thin Provisioning operates at the virtual machine disk (VMDK) level. A VMDK file is allocated as either “thick” or thin provisioned. For example, blocks in the VMDK file are not allocated and backed by physical storage until they are written during the normal course of business. Note that a read to an unallocated block will simply return zeroes, but not back the block with physical storage until it is written.



Thin provisioned VMDKs are created more quickly and optimize the space usage. Once all of the thin or sparse disk’s blocks are allocated, they are no different from a thick disk.

Key features of vSphere Thin Provisioning are:

• Interoperability. The complete operating system and hardware independence allows vSphere Thin Provisioning to connect and provision any tier of storage independent of connectivity.
• Thick to thin migration. Leveraging vSphere Storage vMotion can convert an existing thick format to a thin format.
• Alarms and reporting. Thin Provisioning is integrated with VMware vCenter™ Server. Therefore, you can provide reports and set thresholds to proactively manage growth and capacity. In vSphere 5.0, if an array is compliant, the vSphere Storage API for Array Integration will automatically surface alarms in vCenter Server if the Thin Provisioning warning threshold (75%) is exceeded.

Oversubscription protection. Thin provisioning can lead to oversubscription. Manage oversubscription by Storage vMotion (which enables dynamic migration of VMDKs) or VMFS volume grow (which provides the ability to dynamically increase the size of your datastore.)