During chunk migrations, insert and update operations affecting data within a migrating chunk are not reflected to the recipient shard, resulting in data loss.
Only the following deployments are affected by this issue:
- Sharded clusters where shards run MongoDB versions 3.0.9 or 3.0.10, and
- The balancer is enabled or manual chunk migrations are performed
Standalone nodes, replica set deployments, and sharded clusters with no chunk migrations are not impacted by this issue. No other version of MongoDB is affected.
During a chunk migration, insert and update operations affecting documents in the migrating chunk are not reflected in the recipient shard, leading to data loss.
Users who haven’t disabled the moveParanoia option should be able to recover this data manually.
Neither MongoDB 3.2 nor MongoDB 3.0.8 and earlier are affected by this issue. Users on affected versions should upgrade to 3.0.11 or newer, 3.2.4 or newer as soon as possible.
Alternatively, users should disable the balancer and ensure no manual chunk migrations occur in order to avoid this issue. The balancer can be disabled cluster-wide or on a per-collection basis. See the Documentation section below for more information.
MongoDB versions 3.0.9 and 3.0.10, only.
The fix is included in the 3.0.11 production release.