Release Notes for mongosync 1.19

Compatibility

• Starting in 1.19, mongosync no longer supports migrating from source clusters that run MongoDB 4.4. Additionally, mongosync does not support migrating to destination clusters that run MongoDB 6.0. For updated version compatibility, see MongoDB Server Version Compatibility.

• Drops support for Ubuntu 18.04. Adds support for Amazon Linux 2023 ARM64. See Install on Linux for updated Linux compatibility.

New Features

• Adds indexBuilding object to the /progress API response and logs to report progress on index builds. See progress for more details.

• Adds a feature that automatically reduces the degree of parallelism of collection copy phase writes for small migrations to small destination clusters. For more details, see Collection Copy.

• mongosync automatically optimizes index builds on destination clusters by batching and parallelizing createIndexes commands. For more information and to explicitly configure batching and parallelism, see Index Build Optimizations.

• Adds the estimatedOplogTimeRemaining field to the /progress API response and logs. This field estimates the oplog time available on the source cluster and helps you determine whether the source oplog is large enough for mongosync to complete the migration.

• Adds the warnings field to the /progress API response and logs. mongosync includes this field when the estimated oplog time remaining on the source cluster is too low for a successful migration.

Fixed Issues

• Fixes a bug where the embedded verifier reported a mismatch if a source collection had the autoIndexId collection option, which was deprecated in MongoDB 3.2 and removed in MongoDB 3.4.

• Fixes a bug where the embedded verifier overestimated the amount of memory needed for verification in sharded clusters.

Other Changes

• mongosync logs now include a pid field that indicates the process ID (PID) of the current mongosync process. This helps when a single log file contains logs from multiple mongosync runs.

Live Upgrades

Live upgrades to mongosync 1.19 are not supported.