>=19.0.0
+* ceph: a new --daemon-output-file switch is available for `ceph tell` commands
+ to dump output to a file local to the daemon. For commands which produce
+ large amounts of output, this avoids a potential spike in memory usage on the
+ daemon, allows for faster streaming writes to a file local to the daemon, and
+ reduces time holding any locks required to execute the command. For analysis,
+ it is necessary to retrieve the file from the host running the daemon
+ manually. Currently, only --format=json|json-pretty are supported.
* RGW: GetObject and HeadObject requests now return a x-rgw-replicated-at
header for replicated objects. This timestamp can be compared against the
Last-Modified header to determine how long the object took to replicate.
.. option:: -f {json,json-pretty,xml,xml-pretty,plain,yaml}, --format
- Format of output. Note: yaml is only valid for orch commands.
+ Format of output.
+
+ Note: yaml is only valid for orch commands.
+
+.. option:: --daemon-output-file OUTPUT_FILE
+
+ When using --format=json|json-pretty, you may specify a file name on the
+ host running the daemon to stream output to. Be mindful this is probably
+ not the same machine running the ceph command. So to analyze the output, it
+ will be necessary to fetch the file once the command completes.
+
+ OUTPUT_FILE may also be ``:tmp:``, indicating that the daemon should create
+ a temporary file (subject to configurations tmp_dir and tmp_file_template).
+
+ The ``tell`` command will output json with the path to the output file
+ written to, the size of the file, the result code of the command, and any
+ output produced by the command.
+
+ Note: this option is only used for ``ceph tell`` commands.
.. option:: --connect-timeout CLUSTER_TIMEOUT
Configuration Reference`_ .
+Temporary Directory
+===================
+
+Some operations will cause a daemon to write to a temporary file. These files
+are located according to the ``tmp_dir`` config.
+
+.. confval:: tmp_dir
+
+The ``$TMPDIR`` environment variable is used to initialize the config, if
+present, but may be overriden on the command-line. A default may also
+be set for the cluster using the usual ``ceph config`` API.
+
+The template for the temporary files created by daemons is controlled
+by the ``tmp_file_template`` config.
+
+.. confval:: tmp_file_template
+
+One example where temporary files are created by daemons is the use of the
+``--daemon-output-file=:tmp:`` argument to the ``ceph tell`` command.
+
+
Monitors
========