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+=======================
+ Logging and Debugging
+=======================
+
+Ceph component debug log levels can be adjusted at runtime, while services are
+running. In some circumstances you might want to adjust debug log levels in
+``ceph.conf`` or in the central config store. Increased debug logging can be
+useful if you are encountering issues when operating your cluster. By default,
+Ceph log files are in ``/var/log/ceph``.
+
+.. tip:: Remember that debug output can slow down your system, and that this
+ latency sometimes hides race conditions.
+
+Debug logging is resource intensive. If you encounter a problem in a specific
+component of your cluster, begin troubleshooting by enabling logging for only
+that component of the cluster. For example, if your OSDs are running without
+errors, but your metadata servers are not, enable logging for any specific
+metadata server instances that are having problems. Continue by enabling
+logging for each subsystem only as needed.
+
+.. important:: Verbose logging sometimes generates over 1 GB of data per hour.
+ If the disk that your operating system runs on (your "OS disk") reaches its
+ capacity, the node associated with that disk will stop working.
+
+Whenever you enable or increase the rate of debug logging, make sure that you
+have ample capacity for log files, as this may dramatically increase their
+size. For details on rotating log files, see `Accelerating Log Rotation`_.
+When your system is running well again, remove unnecessary debugging settings
+in order to ensure that your cluster runs optimally. Logging debug-output
+messages is a slow process and a potential waste of your cluster's resources.
+
+For details on available settings, see `Subsystem, Log and Debug Settings`_.
+
+Runtime
+=======
+
+To see the configuration settings at runtime, log in to a host that has a
+running daemon and run a command of the following form:
+
+.. prompt:: bash $
+
+ ceph daemon {daemon-name} config show | less
+
+For example:
+
+.. prompt:: bash $
+
+ ceph daemon osd.0 config show | less
+
+To activate Ceph's debugging output (that is, the ``dout()`` logging function)
+at runtime, inject arguments into the runtime configuration by running a ``ceph
+tell`` command of the following form:
+
+.. prompt:: bash $
+
+ ceph tell {daemon-type}.{daemon id or *} config set {name} {value}
+
+Here ``{daemon-type}`` is ``osd``, ``mon``, or ``mds``. Apply the runtime
+setting either to a specific daemon (by specifying its ID) or to all daemons of
+a particular type (by using the ``*`` operator). For example, to increase
+debug logging for a specific ``ceph-osd`` daemon named ``osd.0``, run the
+following command:
+
+.. prompt:: bash $
+
+ ceph tell osd.0 config set debug_osd 0/5
+
+The ``ceph tell`` command goes through the monitors. However, if you are unable
+to bind to the monitor, there is another method that can be used to activate
+Ceph's debugging output: use the ``ceph daemon`` command to log in to the host
+of a specific daemon and change the daemon's configuration. For example:
+
+.. prompt:: bash $
+
+ sudo ceph daemon osd.0 config set debug_osd 0/5
+
+For details on available settings, see `Subsystem, Log and Debug Settings`_.
+
+
+Boot Time
+=========
+
+To activate Ceph's debugging output (that is, the ``dout()`` logging function)
+at boot time, you must add settings to your Ceph configuration file.
+Subsystems that are common to all daemons are set under ``[global]`` in the
+configuration file. Subsystems for a specific daemon are set under the relevant
+daemon section in the configuration file (for example, ``[mon]``, ``[osd]``,
+``[mds]``). Here is an example that shows possible debugging settings in a Ceph
+configuration file:
+
+.. code-block:: ini
+
+ [global]
+ debug_ms = 1/5
+
+ [mon]
+ debug_mon = 20
+ debug_paxos = 1/5
+ debug_auth = 2
+
+ [osd]
+ debug_osd = 1/5
+ debug_filestore = 1/5
+ debug_journal = 1
+ debug_monc = 5/20
+
+ [mds]
+ debug_mds = 1
+ debug_mds_balancer = 1
+
+
+For details, see `Subsystem, Log and Debug Settings`_.
+
+
+Accelerating Log Rotation
+=========================
+
+If your log filesystem is nearly full, you can accelerate log rotation by
+modifying the Ceph log rotation file at ``/etc/logrotate.d/ceph``. To increase
+the frequency of log rotation (which will guard against a filesystem reaching
+capacity), add a ``size`` directive after the ``weekly`` frequency directive.
+To smooth out volume spikes, consider changing ``weekly`` to ``daily`` and
+consider changing ``rotate`` to ``30``. The procedure for adding the size
+setting is shown immediately below.
+
+#. Note the default settings of the ``/etc/logrotate.d/ceph`` file::
+
+ rotate 7
+ weekly
+ compress
+ sharedscripts
+
+#. Modify them by adding a ``size`` setting::
+
+ rotate 7
+ weekly
+ size 500M
+ compress
+ sharedscripts
+
+#. Start the crontab editor for your user space:
+
+ .. prompt:: bash $
+
+ crontab -e
+
+#. Add an entry to crontab that instructs cron to check the
+ ``etc/logrotate.d/ceph`` file::
+
+ 30 * * * * /usr/sbin/logrotate /etc/logrotate.d/ceph >/dev/null 2>&1
+
+In this example, the ``etc/logrotate.d/ceph`` file will be checked every 30
+minutes.
+
+Valgrind
+========
+
+When you are debugging your cluster's performance, you might find it necessary
+to track down memory and threading issues. The Valgrind tool suite can be used
+to detect problems in a specific daemon, in a particular type of daemon, or in
+the entire cluster. Because Valgrind is computationally expensive, it should be
+used only when developing or debugging Ceph, and it will slow down your system
+if used at other times. Valgrind messages are logged to ``stderr``.
+
+
+Subsystem, Log and Debug Settings
+=================================
+
+Debug logging output is typically enabled via subsystems.
+
+Ceph Subsystems
+---------------
+
+For each subsystem, there is a logging level for its output logs (a so-called
+"log level") and a logging level for its in-memory logs (a so-called "memory
+level"). Different values may be set for these two logging levels in each
+subsystem. Ceph's logging levels operate on a scale of ``1`` to ``20``, where
+``1`` is terse and ``20`` is verbose [#f1]_. As a general rule, the in-memory
+logs are not sent to the output log unless one or more of the following
+conditions obtain:
+
+- a fatal signal is raised or
+- an ``assert`` in source code is triggered or
+- upon requested. Please consult `document on admin socket
+ <http://docs.ceph.com/en/latest/man/8/ceph/#daemon>`_ for more details.
+
+.. warning ::
+ .. [#f1] In certain rare cases, there are logging levels that can take a value greater than 20. The resulting logs are extremely verbose.
+
+Log levels and memory levels can be set either together or separately. If a
+subsystem is assigned a single value, then that value determines both the log
+level and the memory level. For example, ``debug ms = 5`` will give the ``ms``
+subsystem a log level of ``5`` and a memory level of ``5``. On the other hand,
+if a subsystem is assigned two values that are separated by a forward slash
+(/), then the first value determines the log level and the second value
+determines the memory level. For example, ``debug ms = 1/5`` will give the
+``ms`` subsystem a log level of ``1`` and a memory level of ``5``. See the
+following:
+
+.. code-block:: ini
+
+ debug {subsystem} = {log-level}/{memory-level}
+ #for example
+ debug mds balancer = 1/20
+
+The following table provides a list of Ceph subsystems and their default log and
+memory levels. Once you complete your logging efforts, restore the subsystems
+to their default level or to a level suitable for normal operations.
+
++--------------------------+-----------+--------------+
+| Subsystem | Log Level | Memory Level |
++==========================+===========+==============+
+| ``default`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``lockdep`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``context`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``crush`` | 1 | 1 |
++--------------------------+-----------+--------------+
+| ``mds`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``mds balancer`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``mds log`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``mds log expire`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``mds migrator`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``buffer`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``timer`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``filer`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``striper`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``objecter`` | 0 | 1 |
++--------------------------+-----------+--------------+
+| ``rados`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``rbd`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``rbd mirror`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``rbd replay`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``rbd pwl`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``journaler`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``objectcacher`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``immutable obj cache`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``client`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``osd`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``optracker`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``objclass`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``filestore`` | 1 | 3 |
++--------------------------+-----------+--------------+
+| ``journal`` | 1 | 3 |
++--------------------------+-----------+--------------+
+| ``ms`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``mon`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``monc`` | 0 | 10 |
++--------------------------+-----------+--------------+
+| ``paxos`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``tp`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``auth`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``crypto`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``finisher`` | 1 | 1 |
++--------------------------+-----------+--------------+
+| ``reserver`` | 1 | 1 |
++--------------------------+-----------+--------------+
+| ``heartbeatmap`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``perfcounter`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``rgw`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``rgw sync`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``rgw datacache`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``rgw access`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``rgw dbstore`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``javaclient`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``asok`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``throttle`` | 1 | 1 |
++--------------------------+-----------+--------------+
+| ``refs`` | 0 | 0 |
++--------------------------+-----------+--------------+
+| ``compressor`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``bluestore`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``bluefs`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``bdev`` | 1 | 3 |
++--------------------------+-----------+--------------+
+| ``kstore`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``rocksdb`` | 4 | 5 |
++--------------------------+-----------+--------------+
+| ``leveldb`` | 4 | 5 |
++--------------------------+-----------+--------------+
+| ``fuse`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``mgr`` | 2 | 5 |
++--------------------------+-----------+--------------+
+| ``mgrc`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``dpdk`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``eventtrace`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``prioritycache`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``test`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``cephfs mirror`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``cepgsqlite`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore onode`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore odata`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore ompap`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore tm`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore t`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore cleaner`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore epm`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore lba`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore fixedkv tree``| 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore cache`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore journal`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore device`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``seastore backref`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``alienstore`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``mclock`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``cyanstore`` | 0 | 5 |
++--------------------------+-----------+--------------+
+| ``ceph exporter`` | 1 | 5 |
++--------------------------+-----------+--------------+
+| ``memstore`` | 1 | 5 |
++--------------------------+-----------+--------------+
+
+
+Logging Settings
+----------------
+
+It is not necessary to specify logging and debugging settings in the Ceph
+configuration file, but you may override default settings when needed. Ceph
+supports the following settings:
+
+.. confval:: log_file
+.. confval:: log_max_new
+.. confval:: log_max_recent
+.. confval:: log_to_file
+.. confval:: log_to_stderr
+.. confval:: err_to_stderr
+.. confval:: log_to_syslog
+.. confval:: err_to_syslog
+.. confval:: log_flush_on_exit
+.. confval:: clog_to_monitors
+.. confval:: clog_to_syslog
+.. confval:: mon_cluster_log_to_syslog
+.. confval:: mon_cluster_log_file
+
+OSD
+---
+
+.. confval:: osd_debug_drop_ping_probability
+.. confval:: osd_debug_drop_ping_duration
+
+Filestore
+---------
+
+.. confval:: filestore_debug_omap_check
+
+MDS
+---
+
+- :confval:`mds_debug_scatterstat`
+- :confval:`mds_debug_frag`
+- :confval:`mds_debug_auth_pins`
+- :confval:`mds_debug_subtrees`
+
+RADOS Gateway
+-------------
+
+- :confval:`rgw_log_nonexistent_bucket`
+- :confval:`rgw_log_object_name`
+- :confval:`rgw_log_object_name_utc`
+- :confval:`rgw_enable_ops_log`
+- :confval:`rgw_enable_usage_log`
+- :confval:`rgw_usage_log_flush_threshold`
+- :confval:`rgw_usage_log_tick_interval`
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-22 09:51:16 +0000