diff --git a/source/reference/server-status-index.txt b/source/reference/server-status-index.txt index d6097fe2438..1d05e8f911b 100644 --- a/source/reference/server-status-index.txt +++ b/source/reference/server-status-index.txt @@ -305,9 +305,10 @@ The ":ref:`server-status-writebacksqueued`" document reports the number of .. _server-status-example-journaling: -The ":ref:`server-status-journaling`" document reports data that -reflect this :program:`mongod` journaling related operations and -performance: +The ":ref:`server-status-journaling`" document reports on data that +reflect this :program:`mongod` instance's journaling-related operations +and performance during a :wiki:`journal group commit interval +`: .. code-block:: javascript diff --git a/source/reference/server-status.txt b/source/reference/server-status.txt index 2d46d89cc70..fa2ae8a6761 100644 --- a/source/reference/server-status.txt +++ b/source/reference/server-status.txt @@ -986,10 +986,21 @@ Journaling .. status:: dur - The :status:`dur` (for "durability") data structure contains data - regarding MongoDB's journaling. :program:`mongod` must be running - with journaling for these data to appear in the output of - ":dbcommand:`serverStatus`". + The :status:`dur` (for "durability") document contains data + regarding the :program:`mongod`'s journaling-related operations and + performance. :program:`mongod` must be running with journaling for + these data to appear in the output of ":dbcommand:`serverStatus`". + + .. note:: + + The data values are **not** cumulative but are reset on a regular + basis as determined by the :wiki:`journal group commit interval + `. This interval is ~100 + milliseconds (ms) by default (or 30ms if the journal file is on + the same file system as your data files) and is cut by 1/3 when + there is a :dbcommand:`getLastError` command pending. The + interval is configurable using the ``--journalCommitInterval`` + option. See the ":wiki:`Journaling`" wiki page for more information about journaling operations. @@ -998,73 +1009,68 @@ Journaling .. status:: dur.commits - The :status:`dur.commits` value provides the number of commits to the - journal in the last commit interval. - - MongoDB groups commits to the journal to improve performance. By - default the interval is 100 milliseconds (ms), but the interval is - configurable as a run-time option and can range from 2ms to 300ms. + The :status:`dur.commits` provides the number of transactions + written to :term:`journal` during the last :wiki:`journal group + commit interval `. .. status:: dur.journaledMB - The :status:`dur.journaledMB` value provides the amount of data in - megabytes (MB) written to the journal in the last commit interval. - - MongoDB groups commits to the journal to improve performance. By - default the commit interval is 100 milliseconds (ms), but the - interval is configurable as a run-time option and can range from - 2ms to 300ms. + The :status:`dur.journaledMB` provides the amount of data in + megabytes (MB) written to :term:`journal` during the last + :wiki:`journal group commit interval + `. .. status:: dur.writeToDataFilesMB - The :status:`dur.writeToDataFilesMB` value provides the amount of data in - megabytes (MB) written from the journal to the data files in the - last commit interval. - - MongoDB groups Commits to the journal to improve performance. By - default the commit interval is 100 milliseconds (ms), but the - interval is configurable as a run-time option and can range from - 2ms to 300ms. - + The :status:`dur.writeToDataFilesMB` provides the amount of data in + megabytes (MB) written from :term:`journal` to the data files during the + last :wiki:`journal group commit interval `. + .. status:: dur.compression .. versionadded:: 2.0 The :status:`dur.compression` represents the compression ratio of - :term:`journal`. + the data written to the :term:`journal`: + + .. code-block:: javascript + + ( journaled_size_of_data / uncompressed_size_of_data ) .. status:: dur.commitsInWriteLock - The value of the field :status:`dur.commitsInWriteLock` provides a count - of the commits that behind a write lock. Commits in a write lock - are undesirable and may indicate a capacity limitation for the - database. + The :status:`dur.commitsInWriteLock` provides a count of the commits + that occurred while a write lock was held. Commits in a write lock + indicate a MongoDB node under a heavy write load and call for + further diagnosis. .. status:: dur.earlyCommits - The :status:`dur.earlyCommits` value reflects the number of time MongoDB - requested a commit before the scheduled commit interval. Use this - value to ensure that your journal commit interval is not too long - for your deployment - -timeMS -~~~~~~ + The :status:`dur.earlyCommits` value reflects the number of time + MongoDB requested a commit before the scheduled :wiki:`journal group + commit interval `. Use this + value to ensure that your :wiki:`journal group commit interval + ` is not too long for your + deployment. .. status:: dur.timeMS - The :status:`dur.timeMS` data structure provides information about the - performance of the :program:`mongod` instance for journaling operations. + The :status:`dur.timeMS` document provides information about the + performance of the :program:`mongod` instance during the various + phases of journaling in the last :wiki:`journal group commit + interval `. .. status:: dur.timeMS.dt - The :status:`dur.timeMS.dt` value provides, in milliseconds, the length - of time over which MongoDB collected the :status:`dur.timeMS` data. Use - this field to provide context to the adjacent values. + The :status:`dur.timeMS.dt` value provides, in milliseconds, the + amount of time over which MongoDB collected the :status:`dur.timeMS` + data. Use this field to provide context to the other + :status:`dur.timeMS` field values. .. status:: dur.timeMS.prepLogBuffer The :status:`dur.timeMS.prepLogBuffer` value provides, in milliseconds, - the amount of time preparing to write to the journal. Smaller + the amount of time spent preparing to write to the journal. Smaller values indicate better journal performance. .. status:: dur.timeMS.writeToJournal @@ -1083,7 +1089,7 @@ timeMS .. status:: dur.timeMS.remapPrivateView The :status:`dur.timeMS.remapPrivateView` value provides, in - milliseconds, the amount of time remapping copy-on-write memory + milliseconds, the amount of time spent remapping copy-on-write memory mapped views. Smaller values indicate better journal performance. .. _server-status-recordstats: