Storage Awareness

VMware vSphere® API for Storage Awareness (VASA) is the primary control plane API for vSphere. This API allows vSphere to both investigate storage configurations and to set storage properties for arrays that support this functionality. VASA is used by vSphere Virtual Volumes, Virtual SAN and vSphere APIs for IO Filtering (VAIO) as the single unified control plane for vSphere storage. Storage vendors can use the VMware vSphere® API for Storage Awareness (VASA) to provide vSphere with information about specific disk arrays for tighter integration between storage and the virtual infrastructure. The shared information includes details on storage virtualization, including health status, configuration, capacity and thin provisioning. This level of detail can now be passed up through VMware® vCenter Server™ to the user.

  • Configure vSphere Virtual Volumes, Virtual SAN and VAIO capabilities.
  • Gather information around specific disk array features (such as snapshot, deduplication, replication state, RAID levels, and thin or thick provisioned) and status (health, troubleshooting and so on).
  • Make it easy for administrators to select the most appropriate storage resources when a virtual machine is created based on high-level details around capacity, performance and capabilities of the underlying disk.
  • Integrate with other vSphere features, like VMware vSphere Storage DRS and Storage Policy-Based Management (SPBM).
  • These APIs are included with the VMware vSphere® Enterprise Standard, Enterprise and Enterprise Plus Edition™.

IO Filtering

VMware vSphere API for IO Filtering (VAIO) allows third party software developers to add data services to ESXi and vSphere. VAIO is designed to allow fully synchronous access to the IO queue of a Virtual Machine with no changes to the running machine. This means that third party filters can do things like caching and replication dynamically against any VM running on any ESXi host at any time. VAIO is fully integrated with vSphere Storage Policy-Based Management (SBPM) which ensures a simple user experience for the vSphere administrator. The VAIO SDK is available to VMware partners who join the VAIO developer program.

Array Integration

vSphere offers an API to offload specific storage operations to supported disk arrays for unparalleled performance and efficiency. With the vSphere API for Array Integration (VAAI), vSphere can perform key operations faster and consume less CPU, memory and storage bandwidth.


Improve storage I/O performance and reliability by integrating with third-party storage vendor multipath software features.

  • Modular storage architecture allows storage partners to write a plug in for their specific capabilities.
  • Plug ins communicate with the intelligence running in the storage array to determine the best path selection, as well as leverage parallel paths to increase I/O performance and reliability from the vSphere host to the storage array.
  • These APIs are included with the VMware vSphere Standard, Enterprise and Enterprise Plus Editions.

Data Protection

Achieve scalable backup without disrupting applications and users with backup software that leverages the VMware vSphere® Storage APIs - Data Protection. vSphere Storage APIs - Data Protection enables backup software to perform centralized virtual machine backups without the disruption and overhead of running backup tasks from inside each virtual machine.

  • Perform full, differential and incremental virtual machine image backup and restore.
  • Perform file-level virtual machine backup using supported Windows and Linux operating systems.
  • Ensure data consistency by using Microsoft Volume Shadow Copy Services (VSS) for virtual machines running supported Microsoft Windows operating systems.
  • The vSphere Storage APIs - Data Protection is included with all vSphere editions and kits.