Skip to content

Commit f24c883

Browse files
DOCSP-47219 Midsync Reads FAQ (#612) (#613)
* DOCSP-47219-midsync-reads * active voice * internal feedback * MVK feedback (cherry picked from commit 6149617) Co-authored-by: Alison Huh <[email protected]>
1 parent 7aee384 commit f24c883

File tree

2 files changed

+22
-14
lines changed

2 files changed

+22
-14
lines changed

source/faq.txt

Lines changed: 20 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -26,20 +26,26 @@ following the steps in :ref:`c2c-reconfigure-mid-migration`.
2626
Can I perform reads or writes to my destination cluster while ``mongosync`` is syncing?
2727
---------------------------------------------------------------------------------------
2828

29-
You can perform reads at any time during synchronization.
30-
However, ``mongosync`` combines and reorders writes from the source to destination during synchronization,
31-
and also temporarily modifies various collection characteristics.
32-
As a result, the destination is not guaranteed to match the source at any point in time when the sync is running.
33-
For consistent reads, wait for the migration to :ref:`c2c-api-commit`. To learn more, see :ref:`mongosync-considerations`.
34-
35-
Performing writes to your destination cluster during synchronization results in undefined behavior.
36-
``mongosync`` blocks writes on the destination cluster by default. To learn
37-
more about write-blocking, see :ref:`c2c-write-blocking` and :ref:`c2c-api-start`.
38-
39-
Upon commit, it is only safe to write to the destination cluster when ``canWrite`` is ``true``.
40-
To check the value of ``canWrite``, run the :ref:`c2c-api-progress` endpoint.
41-
42-
To learn more about permissable reads and writes during synchronization, see :ref:`c2c-reads-and-writes`.
29+
``mongosync`` :ref:`combines and reorders <c2c-behavior-consistency>` writes
30+
from the source to destination during synchronization, and
31+
:ref:`temporarily modifies <c2c-behavior-temporary-changes>` collection
32+
characteristics. As a result, ``mongosync`` can't guarantee that the destination
33+
matches the source, including a stale version of the source, at any point in
34+
time when the sync is running, even if the sync is paused. To safely accept
35+
traffic to the destination cluster, wait for the migration to
36+
:ref:`c2c-api-commit`. To learn more, see :ref:`mongosync-considerations`.
37+
38+
Performing writes to your destination cluster during synchronization results in
39+
undefined behavior. ``mongosync`` blocks writes on the destination cluster by
40+
default. To learn more about write-blocking, see :ref:`c2c-write-blocking` and
41+
:ref:`c2c-api-start`.
42+
43+
Upon commit, it is only safe to write to the destination cluster when
44+
``canWrite`` is ``true``. To check the value of ``canWrite``, run the
45+
:ref:`c2c-api-progress` endpoint.
46+
47+
To learn more about permissable reads and writes during synchronization, see
48+
:ref:`c2c-reads-and-writes`.
4349

4450
.. note::
4551

source/reference/mongosync/mongosync-behavior.txt

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -232,6 +232,8 @@ snapshot of the source data. To learn more, see :ref:`c2c-behavior-consistency`.
232232
Otherwise, start a new continuous sync operation by using a new empty
233233
destination cluster.
234234

235+
.. _c2c-behavior-temporary-changes:
236+
235237
Temporary Changes to Collection Characteristics
236238
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
237239

0 commit comments

Comments
 (0)