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DOCSP-38679 mongoexport consistency consideration #166

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Jul 22, 2024
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DOCSP-38679 mongoexport consistency consideration #166

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DOCSP-38679 mongoexport consistency consideration
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DOCSP-38679 mongoexport consistency consideration
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12 changes: 12 additions & 0 deletions source/mongodump.txt
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Expand Up @@ -224,6 +224,18 @@ Syntax
.. tab:: Connect to a Sharded Cluster
:tabid: connect-to-a-sharded-cluster

.. note::

To avoid data inconsistencies, pause the following actions on your
sharded cluster when you run ``mongodump``:

- Cross-shard transactions
- Data definition language operations (operations that create and modify
collections)
- Chunk balancing
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Could we instead advise users to pause all writes and turn off balancers? Certain operations may use transactions implicitly under the hood. There could also be race conditions between turning off writes and finishing any in-flight operations, so users should make certain that the cluster has fully quiesced before attempting any snapshots. Ditto this comment for mongoexport as well

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Hey @ltran-mdb2 just wanted to follow-up on this. Let me know if this needs a separate ticket - thanks!

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Hi @mvankeulen94 , sorry for the delay! Could you create a separate ticket for this?

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Filed https://jira.mongodb.org/browse/DOCSP-41895, thank you! Please feel free to reassign if needed

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Ideally rather than having this blurb here, we could instead restate the disclaimer that these tools are not intended for taking backups, and to see https://www.mongodb.com/docs/manual/administration/backup-sharded-clusters/ for how to back up sharded clusters.


To stop the balancer, use the :method:`sh.stopBalancer()` method.

To connect to a sharded cluster to export its data, you can:

- Specify the hostname of the ``mongos`` instance in the
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15 changes: 15 additions & 0 deletions source/mongoexport.txt
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Expand Up @@ -39,6 +39,9 @@ or CSV export of data stored in a MongoDB instance.
Run ``mongoexport`` from the system command line, not the
:binary:`~bin.mongo` shell.

``mongoexport`` is not a tool for backing up deployments. If you want to
create a backup solution, see :ref:`manual-tutorial-backup-and-restore`.

.. seealso::

:binary:`~bin.mongoimport` which provides the corresponding
Expand Down Expand Up @@ -171,6 +174,18 @@ For more information on the options available, see :ref:`mongoexport-options`.
Connect to a Sharded Cluster
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note::

To avoid data inconsistencies, pause the following actions on your
sharded cluster when you run ``mongoexport``:

- Cross-shard transactions
- Data definition language operations (operations that create and modify
collections)
- Chunk balancing

To stop the balancer, use the :method:`sh.stopBalancer()` method.

To connect to a sharded cluster to export its data, you can either:

- Specify the hostname of the :binary:`~bin.mongos` instance in the
Expand Down