# Key concepts

## Share

In the Shared File Systems service `share` is the fundamental resource unit allocated by the Shared File System service. It represents an allocation of a persistent, readable, and writable filesystems. Compute instances access these filesystems. Depending on the deployment configuration, clients outside of OpenStack can also access the filesystem.

Note

A `share` is an abstract storage object that may or may not directly map to a “share” concept from the underlying storage provider. See the description of `share instance` for more details.

## Share instance

This concept is tied with `share` and represents created resource on specific back end, when `share` represents abstraction between end user and back-end storages. In common cases, it is one-to-one relation. One single `share` has more than one `share instance` in two cases:

- When `share migration` is being applied

- When `share replication` is enabled

Therefore, each `share instance` stores information specific to real allocated resource on storage. And `share` represents the information that is common for `share instances`. A user with `member` role will not be able to work with it directly. Only a user with `admin` role has rights to perform actions against specific share instances.

## Snapshot

A `snapshot` is a point-in-time, read-only copy of a `share`. You can create `Snapshots` from an existing, operational `share` regardless of whether a client has mounted the file system. A `snapshot` can serve as the content source for a new `share`. Specify the Create from snapshot option when creating a new `share` on the dashboard.

## Storage Pools

With the Kilo release of OpenStack, Shared File Systems can use `storage pools`. The storage may present one or more logical storage resource pools that the Shared File Systems service will select as a storage location when provisioning `shares`.

## Share Type

`Share type` is an abstract collection of criteria used to characterize `shares`. They are most commonly used to create a hierarchy of functional capabilities. This hierarchy represents tiered storage services levels. For example, an administrator might define a premium `share type` that indicates a greater level of performance than a basic `share type`. Premium represents the best performance level.

## Share Access Rules

`Share access rules` define which users can access a particular `share`. For example, administrators can declare rules for NFS shares by listing the valid IP networks which will access the `share`. List the IP networks in CIDR notation.

## Security Services

`Security services` allow granular client access rules for administrators. They can declare rules for authentication or authorization to access `share` content. External services including LDAP, Active Directory, and Kerberos can be declared as resources. Examine and consult these resources when making an access decision for a particular `share`. You can associate `Shares` with multiple security services, but only one service per one type.

## Share Networks

A `share network` is an object that defines a relationship between a project network and subnet, as defined in an OpenStack Networking service or Compute service. The `share network` is also defined in `shares` created by the same project. A project may find it desirable to provision `shares` such that only instances connected to a particular OpenStack-defined network have access to the `share`. Also, `security services` can be attached to `share networks`, because most of auth protocols require some interaction with network services.

The Shared File Systems service has the ability to work outside of OpenStack. That is due to the `StandaloneNetworkPlugin`. The plugin is compatible with any network platform, and does not require specific network services in OpenStack like Compute or Networking service. You can set the network parameters in the `manila.conf` file.

## Share Servers

A `share server` is a logical entity that hosts the shares created on a specific `share network`. A `share server` may be a configuration object within the storage controller, or it may represent logical resources provisioned within an OpenStack deployment used to support the data path used to access `shares`.

`Share servers` interact with network services to determine the appropriate IP addresses on which to export `shares` according to the related `share network`. The Shared File Systems service has a pluggable network model that allows `share servers` to work with different implementations of the Networking service.

this page last updated: 2026-03-20 00:30:00

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