Git-annex supports several levels of trust of a repository:

* semitrusted (default)
* untrusted
* trusted
* dead

## semitrusted

Normally, git-annex does not fully trust its stored [[location_tracking]]
information. When removing content, it will directly check
that other repositories have enough [[copies]].

Generally that explicit checking is a good idea. Consider that the current
[[location_tracking]] information for a remote may not yet have propagated
out. Or, a remote may have suffered a catastrophic loss of data, or itself
been lost.

There is still some trust involved here. A semitrusted repository is
depended on to retain a copy of the file content; possibly the only
[[copy|copies]].

(Being semitrusted is the default. The [[git-annex semitrust|git-annex-semitrust]] command
restores a repository to this default, when it has been overridden.
The `--semitrust` option can temporarily restore a repository to this
default.)

## untrusted

An untrusted repository is not trusted to retain data at all. Git-annex
will retain sufficient [[copies]] of data elsewhere.

This is a good choice for eg, portable drives that could get lost. Or,
if a disk is known to be dying, you can set it to untrusted and let
`git annex fsck` warn about data that needs to be copied off it.

To configure a repository as untrusted, use the [[git-annex untrust|git-annex-untrust]]
command.

## trusted

Sometimes, you may have reasons to fully trust the location tracking
information for a repository. For example, it may be an offline
archival drive, from which you rarely or never remove content. Deciding
when it makes sense to trust the tracking info is up to you.

To configure a repository as fully and permanently trusted,
use the [[git-annex-trust]] command.

Note that after dropping content from a trusted repo, other repos
that are out of sync and trust it to still contain the content
can drop copies, even though that will violate [[numcopies]]. So
using trusted repositories can lead to data loss. It is best to take
extreme care when dropping content from trusted repositories,
the same as if you were using `--force`.

## dead

This is used to indicate that you have no trust that the repository
exists at all. It's appropriate to use when a drive has been lost,
or a directory irretrievably deleted. It will make git-annex avoid
even showing the repository as a place where data might still reside.

To configure a repository as dead and lost, use the [[git-annex-dead]]
command.