Cinder Volume Type Metadata Tutorial

Platform9's Volume Type Metadata is another name for OpenStack Cinder's Volume Type Extra Specs.

Cinder Volume Extra Specs are vendor and driver supplied metadata. Users can use these as extra filter criteria for the Block Storage scheduler to use for determining which Block Storage host should fulfill a volume creation request.

Driver supplied metadata

Each driver provides a vendor_name key-value pair which indicates the company or entity behind the driver. For example, the SolidFire driver has vendor_name = SolidFire Inc . The NetApp iSCSI driver has vendor_name = NetApp . Suppose we have appliances from NetApp and SolidFire.

To schedule volume creation on NetApp appliances only, create a Volume Type, say, NetApp-Volume with extra metadata vendor_name set to NetApp .

Figure 1. Volume Type NetApp-Volume schedules all volume creation to NetApp appliances.

To schedule volume creation on SolidFire appliances only, can create a Volume Type, say, SolidFire-Volume with extra metadata vendor_name set to SolidFire Inc .

Figure 2. Volume Type SolidFire-Volume schedules all volume creation to SolidFire appliances.

For more information on driver supplied metadata please read your storage driver's manual.

Vendor supplied metadata

A vendor may also expose several extra metadata that may help fine tune volume creation scheduling. For example, some NetApp appliances support netapp_compression .  This 'extra spec', if set to true, limits volume creation to NetApp storage controllers that have compression enabled.

For more information on vendor supplied metadata/extra specs, please read your storage vendor's manual.

Volume Type Metadata in VMware

You can use Volume Type metadata in VMware to setup storage policy based management to designate which datastores to use for volumes. For more details, refer to this article.


January 28, 2016