Manila/Concepts
Contents
Manila Concepts
This is a guide to various terms used in the Manila project, explaining what they mean, who they apply to, and where they matter.
A share is a unit of storage with a protocol, a size, and an access list. Shares are the basic primitive provided by Manila. All shares exist on a backend. Some shares are associated with share_networks and share_servers.
- Tenants can create, delete, list, get details, snapshot, and modify access for shares.
- Administrators typically don't interact with shares except to debug problems.
- Inside Manila, a share is just a row in a database table.
- Vendors/drivers implement shares using software and/or hardware however they wish.
snapshot
A snapshot is a point in time copy of a share. Snapshots can only be used to create new shares (containing the snapshotted data). Shares can not be deleted until all associated snapshots are deleted.
- Tenants can create, delete, and list snapshots, and can create new shares from snapshots.
- Administrators typically don't interact with snapshots, except to debug problems.
- Inside Manila, a snapshot is just a row in a database table, linked to a share.
- Vendors/drivers implements snapshots using whatever technology makes sense for their backend.
A share_type is an administrator-defined "type of service", comprised of a tenant visible description, and a list of non-tenant-visible key/value pairs (extra_specs) which the Manila scheduler uses to make scheduling decisions.
- Tenants can list share_types and can use them to create new shares.
- Administrators create and delete share_types, and manage the extra_specs that give them meaning inside Manila.
- Inside Manila, share_types are used by the scheduler to make scheduling decisions, and used by drivers to control share creation.
- Vendors/drivers can see the share_type and associated extra_specs when creating new shares, and can configure backend-specific options based on those values.
extra_spec
Extra_specs are the key/value pairs associated with share_types. The valid keys and values are defined by Manila and its drivers
