Volume types
Learn which volume types Block Storage offers, how a region decides which types are available, how each type is billed, and how encryption is handled.
A volume type is the storage tier that a volume is provisioned on. The type decides which storage class the cloud uses for the volume and the rate that the volume is billed at. You choose the type when you create a volume.
The types
Block Storage has three volume types:
| Type | Notes |
|---|---|
| Premium SSD | Offered where the region provides a storage class for it. |
| Standard SSD | Always offered where the region offers Block Storage. OS disks use it, and new data disks in the instance wizard start with it. |
| Standard HDD | Offered where the region provides a storage class for it. |
The region's operator maps each type to a storage class of the cloud. A type is available in a region only when that storage class exists there, except Standard SSD, which uses the cloud's default storage class and is always available. The create form lists only the types that the region offers, so you can't select a type that the region can't provision. An API request for an unavailable type is refused.
For example, if a region provides only its default storage class, the create form offers Standard SSD alone.
To read the types that a region offers and their prices, use GET/regions/{region}/volume-types.
Price per type
Each type is billed at its own rate per GB-month, for the volume's provisioned size. The create form shows each type's rate per GB-month. When a region publishes no price for a type, the form shows a dash instead of a price.
Volume storage is billed for as long as the volume exists, whether it's attached or not. For how billing works, see What is Block Storage?.
Types of OS disks and data disks
When you create an instance, the creation wizard creates its OS disk on Standard SSD. The wizard shows the type, and you can't change it. Data disks that you add in the wizard can use any type that the region offers. See Create a virtual machine.
Change the type of a volume
Changing the type of a volume is available through the API only. Use POST/scopes/{scopeId}/storage/volumes/{volumeId}/actions/retype. The change runs in the background, and these rules apply:
- The volume must be detached, with the status Available. Otherwise, the request is refused with "volume must be AVAILABLE to change its category; detach it first".
- The new type must differ from the current type, or the request is refused with "volume is already on this category". The region must offer the new type.
- The new type's rate applies from the next full hour. The hour in which you change the type is billed at the old type's rate.
Volumes without a type
A volume that came from an imported project can sit on a storage class that no type maps to. Such a volume shows the storage class's own name, marked as an unpriced type, and it isn't billed.
Encryption at rest
Encryption at rest is available only where the region supports it; the console shows the option only there. A volume's Encryption property on its Overview tab shows what the cloud reports for the volume. For how the platform handles encryption, see Encryption.