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https://github.com/ceph/ceph
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97 lines
2.3 KiB
ReStructuredText
97 lines
2.3 KiB
ReStructuredText
==================
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Memory Profiling
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==================
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Ceph OSD and metadata server daemons can generate heap profiles using
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``tcmalloc``. To generate heap profiles, ensure you have ``google-perftools``
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installed::
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sudo apt-get google-perftools
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The profiler dumps output to your ``log file`` directory (i.e.,
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``/var/log/ceph``). See `Logging and Debugging`_ for details.
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To view the profiler logs with Google's performance tools, execute the
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following::
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google-pprof -gv {log-path/filename}
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Refer to `Google Heap Profiler`_ for additional details.
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Once you have the heap profiler installed, start your cluster and begin using
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the heap profiler. You may enable or disable the heap profiler at runtime, or
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ensure that it runs continuously. For the following commandline usage, replace
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``{daemon-type}`` with ``osd`` or ``mds``, and replace ``daemon-id`` with the
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OSD number or metadata server letter.
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Starting the Profiler
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---------------------
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To start the heap profiler, execute the following::
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ceph {daemon-type} tell {daemon-id} heap start_profiler
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For example::
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ceph osd tell 1 heap start_profiler
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Printing Stats
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--------------
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To print out statistics, execute the following::
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ceph {daemon-type} tell {daemon-id} heap stats
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For example::
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ceph osd tell 0 heap stats
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.. note:: Printing stats does not require the profiler to be running and does
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not dump the heap allocation information to a file.
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Dumping Heap Information
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------------------------
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To dump heap information, execute the following::
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ceph {daemon-type} tell {daemon-id} heap dump
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For example::
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ceph mds tell a heap dump
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.. note:: Dumping heap information only works when the profiler is running.
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Releasing Memory
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----------------
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To release memory that ``tcmalloc`` has allocated but which is not being used by
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the Ceph daemon itself, execute the following::
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ceph {daemon-type} tell {daemon-id} heap release
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For example::
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ceph osd tell 2 heap release
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Stopping the Profiler
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---------------------
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To stop the heap profiler, execute the following::
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ceph {daemon-type} tell {daemon-id} heap stop_profiler
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For example::
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ceph {daemon-type} tell {daemon-id} heap stop_profiler
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.. _Logging and Debugging: ../log-and-debug
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.. _Google Heap Profiler: http://google-perftools.googlecode.com/svn/trunk/doc/heapprofile.html
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