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| -rw-r--r-- | doc/rados/operations/index.rst | 1 | ||||
| -rw-r--r-- | doc/rados/operations/memory-profiling.rst | 96 |
2 files changed, 97 insertions, 0 deletions
diff --git a/doc/rados/operations/index.rst b/doc/rados/operations/index.rst index 032b567bc90..fca327a89b0 100644 --- a/doc/rados/operations/index.rst +++ b/doc/rados/operations/index.rst @@ -15,6 +15,7 @@ and, monitoring an operating cluster. operating monitoring cpu-profiling + memory-profiling troubleshooting debug diff --git a/doc/rados/operations/memory-profiling.rst b/doc/rados/operations/memory-profiling.rst new file mode 100644 index 00000000000..dc46dcc888c --- /dev/null +++ b/doc/rados/operations/memory-profiling.rst @@ -0,0 +1,96 @@ +================== + Memory Profiling +================== + +Ceph OSD and metadata server daemons can generate heap profiles using +``tcmalloc``. To generate heap profiles, ensure you have ``google-perftools`` +installed:: + + sudo apt-get google-perftools + +The profiler dumps output to your ``log file`` directory (i.e., +``/var/log/ceph``). See `Logging and Debugging Config Reference`_ for details. +To view the profiler logs with Google's performance tools, execute the +following:: + + google-pprof -gv {log-path/filename} + +Refer to `Google Heap Profiler`_ for additional details. + +Once you have the heap profiler installed, start your cluster and begin using +the heap profiler. You may enable or disable the heap profiler at runtime, or +ensure that it runs continously. For the following commandline usage, replace +``{daemon-type}`` with ``osd`` or ``mds``, and replace ``daemon-id`` with the +OSD number or metadata server letter. + + +Starting the Profiler +--------------------- + +To start the heap profiler, execute the following:: + + ceph {daemon-type} tell {daemon-id} heap start_profiler + +For example:: + + ceph osd tell 1 heap start_profiler + + +Printing Stats +-------------- + +To print out statistics, execute the following:: + + ceph {daemon-type} tell {daemon-id} heap stats + +For example:: + + ceph osd tell 0 heap stats + +.. note:: Printing stats does not require the profiler to be running and does + not dump the heap allocation information to a file. + + +Dumping Heap Information +------------------------ + +To dump heap information, execute the following:: + + ceph {daemon-type} tell {daemon-id} heap dump + +For example:: + + ceph mds tell a heap dump + +.. note:: Dumping heap information only works when the profiler is running. + + +Releasing Memory +---------------- + +To release memory that ``tcmalloc`` has allocated but which is not being used by +the Ceph daemon itself, execute the following:: + + ceph {daemon-type} tell {daemon-id} heap release + +For example:: + + ceph osd tell 2 heap release + + +Stopping the Profiler +--------------------- + +To stop the heap profiler, execute the following:: + + ceph {daemon-type} tell {daemon-id} heap stop_profiler + +For example:: + + ceph {daemon-type} tell {daemon-id} heap stop_profiler + +.. _Logging and Debugging Config Reference: ../../configuration/log-and-debug-ref +.. _Google Heap Profiler: http://google-perftools.googlecode.com/svn/trunk/doc/heapprofile.html + + + |