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Sep 25, 2012
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Server status dur1 #258

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de260b4
DOCS-436 add to serverStatus().dur documentation
kay-kim Sep 24, 2012
4f5f338
DOCS-436 add to serverStatus().dur documentation
kay-kim Sep 24, 2012
1e677be
DOCS-436 serverStatus.dur documentation
kay-kim Sep 25, 2012
c4a5d57
DOCS-436 serverStatus dur documentation
kay-kim Sep 25, 2012
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7 changes: 4 additions & 3 deletions source/reference/server-status-index.txt
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Expand Up @@ -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
<Journaling#Journaling-GroupCommits>`:

.. code-block:: javascript

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96 changes: 51 additions & 45 deletions source/reference/server-status.txt
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Expand Up @@ -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
<Journaling#Journaling-GroupCommits>`. 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.
Expand All @@ -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 <Journaling#Journaling-GroupCommits>`.

.. 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
<Journaling#Journaling-GroupCommits>`.

.. 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 <Journaling#Journaling-GroupCommits>`.

.. 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 <Journaling#Journaling-GroupCommits>`. Use this
value to ensure that your :wiki:`journal group commit interval
<Journaling#Journaling-GroupCommits>` 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 <Journaling#Journaling-GroupCommits>`.

.. 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
Expand All @@ -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:
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