## backends.Tier


The cumulative capability tier of a backend (or of one object).


Usage

``` python
backends.Tier
```


## Attributes

| Name | Description |
|----|----|
| [ADDRESSABLE](#ADDRESSABLE) | Committed state can be read back; nothing to create or GC. |
| [FORKABLE](#FORKABLE) | [new](vcs.VcsAdapter.md#tether.vcs.VcsAdapter.new) forks writable branches; [open](testing.ObjectBackend.md#tether.testing.ObjectBackend.open) returns writable handles. |
| [OBSERVED](#OBSERVED) | Drift detection only; committed state is not recoverable. |
| [PINNABLE](#PINNABLE) | Commit creates a durable native ref; [verify](ObjectStatus.md#tether.ObjectStatus.verify) and `gc` apply. |

------------------------------------------------------------------------


#### ADDRESSABLE


Committed state can be read back; nothing to create or GC.


`ADDRESSABLE=``"addressable"`


------------------------------------------------------------------------


#### FORKABLE


[new](vcs.VcsAdapter.md#tether.vcs.VcsAdapter.new) forks writable branches; [open](testing.ObjectBackend.md#tether.testing.ObjectBackend.open) returns writable handles.


`FORKABLE=``"forkable"`


------------------------------------------------------------------------


#### OBSERVED


Drift detection only; committed state is not recoverable.


`OBSERVED=``"observed"`


------------------------------------------------------------------------


#### PINNABLE


Commit creates a durable native ref; [verify](ObjectStatus.md#tether.ObjectStatus.verify) and `gc` apply.


`PINNABLE=``"pinnable"`