Release Notes for mongosync 1.11

Destination-Only Write-Blocking

By default, mongosync enables destination-only write-blocking on the destination cluster. mongosync unblocks writes right before the /progress endpoint reports that canWrite is true. You can explicitly enable destination-only write-blocking by using the /start endpoint to set enableUserWriteBlocking to "destinationOnly".

You can enable dual write-blocking. If you enable dual write-blocking, mongosync blocks writes:

• On the destination cluster during the migration. mongosync unblocks writes right before it sets canWrite to true

• On the source cluster after you call /commit

To enable dual write-blocking, use /start to set enableUserWriteBlocking to "sourceAndDestination".

You can use /start to set enableUserWriteBlocking to "none".

You cannot enable dual write-blocking or disable write-blocking after the sync starts.

Live Upgrades

Starting in version 1.11.0, mongosync does not support Live Upgrades.

Permissions

mongosync requires additional permissions on Atlas destination clusters for default migrations. See Atlas Clusters.

Other Notes

Fixed Issues:

• Fixed a bug introduced in v1.9.0, where the embedded verifier could incorrectly report a failure if a collection with a TTL index was renamed and later recreated without a TTL index.

• Fixed a bug introduced in v1.0.0 where a prepareUnique index could be made unique on the destination collection or a previously unique index could be left in a prepareUnique state on the destination collection after cutover.