[[misc-cluster]]
=== Miscellaneous cluster settings

[[cluster-read-only]]
==== Metadata

An entire cluster may be set to read-only with the following _dynamic_ setting:

`cluster.blocks.read_only`::

      Make the whole cluster read only (indices do not accept write
      operations), metadata is not allowed to be modified (create or delete
      indices).

WARNING: Don't rely on this setting to prevent changes to your cluster. Any
user with access to the <<cluster-update-settings,cluster-update-settings>>
API can make the cluster read-write again.


[[cluster-logger]]
==== Logger

The settings which control logging can be updated dynamically with the
`logger.` prefix.  For instance, to increase the logging level of the
`indices.recovery` module to `DEBUG`, issue this request:

[source,json]
-------------------------------
PUT /_cluster/settings
{
  "transient": {
    "logger.indices.recovery": "DEBUG"
  }
}
-------------------------------