Tiered storage is the assignment of different categories of data to different types of storage media in order to reduce total storage cost. vCloud Air offers two storage tiers for virtual machines.

Standard Storage

Standard storage provides traditional block storage for virtual machines. Standard storage is lower cost and appropriate for storage of tier 2 and tier 3 data. Tier 2 and tier 3 include data that is seldom-used or event driven.

Examples of tier 2 and tier 3 data include large data sets, such as log file storage and archival of large sets of static data.

SSD-Accelerated Storage

SSD-Accelerated storage provides higher performance block storage for virtual machines. SSD-Accelerated storage is appropriate for all tiers (1, 2, and 3); though, it is most recommended for tier 1 data. Tier 1 includes data that is mission-critical, frequently accessed, or requires a high degree of security.

Examples of tier 1 data include a high-access database, which is part of a three-tier application, a host cache, or a virtual machine boot (primary) disk.

Migrating virtual machine disks between tiers has no impact on virtual machine uptime or availability; for example, when moving a virtual machine disk to the other storage tier, the virtual machine can remain powered on and accessible.

You can allocate storage to a virtual machine on a per-disk basis; for example, a virtual machine with two disks could have one disk utilizing SSD-Accelerated storage and the other disk utilizing Standard storage.

Adjusting storage allocation for a virtual machine does not impact existing snapshots for the virtual machine; for example, when expanding disk storage for a virtual machine, you do not need to snapshot the virtual machine before expanding the storage.

While the total subscribed storage can be fully allocated to one or more Virtual Data Centers, some storage is reserved for operational overhead, including swap files and catalogs. This prevents you from fully provisioning the storage allocation to virtual machines. For further information, please review this Knowledge Base article: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2043173.

There are several ways to view your storage allocation in the vCloud Air (formerly known as vCloud Hybrid Service) console.

Administrators can view allocated storage at a virtual data center level:

As a list of virtual data centers for all regions by selecting All Cloud Regions from the drop-down menu at the top of the console

View Storage Across Regions

vCloud Air displays all virtual data centers in the selected cloud. (The regions menu is available when you have vCloud Air resources in multiple regions.)

For all virtual data centers in a region by selecting a region from the drop-down menu and clicking the arrow next to Storage under Resource Snapshot

View Storage for a Cloud

For a virtual data center by selecting the virtual data center in the Dashboard and viewing the storage information on the Usage & Allocation tab of the Virtual Data Center Details page

View Storage for a Virtual Data Center

For a selected virtual machine within a virtual data center by selecting the virtual data center in the Dashboard, clicking the Virtual Machines tab, then the virtual machine name for which to view storage information

The Setting tab appears for the virtual machine. The storage information is appears in the Disks row.

View Storage for a Virtual Machine

Users can view allocated storage for their virtual machines:

For selected virtual machines by clicking the Virtual Machines tab from the Dashboard, clicking the virtual machine name for which to view storage information

The Setting tab appears for the virtual machine. The storage information is appears in the Disks row.