.. _minio-bucket-replication-resynchronize: ======================================== Resynchronize Bucket from Remote Replica ======================================== .. default-domain:: minio .. contents:: Table of Contents :local: :depth: 1 The procedure on this page resynchronizes the contents of a MinIO bucket using a healthy replication remote. Resynchronization supports recovery after partial or total loss of data on a MinIO deployment in a replica configuration. For example, consider a MinIO active-active replication configuration similar to the following: .. image:: /images/replication/active-active-twoway-replication.svg :width: 600px :alt: Active-Active Replication synchronizes data between two remote deployments. :align: center Resynchronization allows using the healthy data on one of the participating MinIO deployments as the source for rebuilding the other deployment. Resynchronization is a per-bucket process. You must repeat resynchronization for each bucket on the remote which suffered partial or total data loss. .. admonition:: Professional Support during BC/DR Operations :class: important `MinIO SUBNET `__ users can `log in `__ and create a new issue related to resynchronization. Coordination with MinIO Engineering via SUBNET can ensure successful resynchronization and restoration of normal operations, including performance testing and health diagnostics. Community users can seek support on the `MinIO Community Slack `__. Community Support is best-effort only and has no SLAs around responsiveness. .. _minio-bucket-replication-serverside-resynchronize-requirements: Requirements ------------ MinIO Deployments Must Be Online ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Resynchronization requires both the source and target deployments be online and able to accept read and write operations. The source *must* have complete network connectivity to the remote. The remote deployment may be "unhealthy" in that it has suffered partial or total data loss. Resynchronization addresses the data loss as long as both source and destination maintain connectivity. Resynchronization Requires Existing Replication Configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Resynchronization requires the healthy source deployment have an existing replication configuration for the unhealthy target bucket. Additionally, resynchronization only applies to those replication rules created with the :ref:`existing object replication ` option. Use :mc:`mc replicate ls` to review the configured replication rules and targets for the healthy source bucket. Replication Requires Matching Object Encryption Settings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. include:: /includes/common-replication.rst :start-after: start-replication-encrypted-objects :end-before: end-replication-encrypted-objects Replication Requires MinIO Deployments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. include:: /includes/common-replication.rst :start-after: start-replication-minio-only :end-before: end-replication-minio-only Replication Requires Versioning ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. include:: /includes/common-replication.rst :start-after: start-replication-requires-versioning :end-before: end-replication-requires-versioning Replication Requires Matching Object Locking State ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. include:: /includes/common-replication.rst :start-after: start-replication-requires-object-locking :end-before: end-replication-requires-object-locking Considerations -------------- Resynchronization Requires Time ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Resynchronization is a background processes that continually checks objects in the source MinIO bucket and copies them to the remote as-needed. The time required for replication to complete may vary depending on the number and size of objects, the throughput to the remote MinIO deployment, and the load on the source MinIO deployment. Total time for completion is generally not predictable due to these variables. MinIO recommends configuring load balancers or proxies to direct traffic only to the healthy cluster until synchronization completes. The following commands can provide insight into the resynchronization status: - :mc-cmd:`mc replicate resync status` on the source to track the resynchronization progress. - :mc:`mc replicate status` on the source and remote to track normal replication data. - Run ``mc ls -r --versions ALIAS/BUCKET | wc -l`` against both source and remote to validate the total number of objects and object versions on each. Resynchronize Objects after Data Loss ------------------------------------- This procedure uses an existing :ref:`MinIO replication configuration ` to restore missing data to one of the MinIO deployments participating in that configuration. Specifically, a healthy MinIO deployment (the ``SOURCE``) synchronizes it's existing data to the unhealthy MinIO deployment (the ``TARGET``). This procedure assumes an existing :ref:`alias ` for the ``SOURCE`` that has the :ref:`necessary permissions ` for configuring replication. You can repeat this procedure for each bucket that requires resynchronization. You can have no more than one replication job running per bucket. 1) List the Configured Replication Targets on the Healthy Source ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Run the :mc:`mc replicate ls` command to list the configured remote targets on the healthy ``SOURCE`` deployment for the ``BUCKET`` that requires resynchronization. .. code-block:: shell :class: copyable mc replicate ls SOURCE/BUCKET --json - Replace ``SOURCE`` with the :ref:`alias ` of the source MinIO deployment. - Replace ``BUCKET`` with the name of the bucket to use as the source for resynchronization. The output resembles the following: .. code-block:: shell :emphasize-lines: 16 { "op": "", "status": "success", "url": "", "rule": { "ID": "cer1tuk9a3p5j68crk60", "Status": "Enabled", "Priority": 0, "DeleteMarkerReplication": { "Status": "Enabled" }, "DeleteReplication": { "Status": "Enabled" }, "Destination": { "Bucket": "arn:minio:replication::UUID:BUCKET" }, "Filter": { "And": {}, "Tag": {} }, "SourceSelectionCriteria": { "ReplicaModifications": { "Status": "Enabled" } }, "ExistingObjectReplication": { "Status": "Enabled" } } } Each document in the output represents one configured replication rule. The ``Destination.Bucket`` field specifies the ARN for a given rule on the bucket. Identify the correct ARN for the Bucket from which you want to resynchronize objects. 2) Start the Resynchronization Procedure ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Run the :mc-cmd:`mc replicate resync start` command to begin the resynchronization process: .. code-block:: shell :class: copyable mc replicate resync start --remote-bucket "arn:minio:replication::UUID:BUCKET" SOURCE/BUCKET - Replace the ``--remote-bucket`` value with the ARN of the unhealthy ``BUCKET`` on the ``TARGET`` MinIO deployment. - Replaced ``SOURCE`` with the :ref:`alias ` of the source MinIO deployment. - Replace the ``BUCKET`` with the name of the bucket on the healthy ``SOURCE`` MinIO deployment. The command returns a resynchronization job ID indicating that the process has begun. 3) Monitor Resynchronization ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Use the :mc-cmd:`mc replicate resync status` command on the source deployment to track the received replication data: .. code-block:: shell :class: copyable mc replicate resync status ALIAS/BUCKET The output resembles the following: .. code-block:: shell mc replicate resync status /data Resync status summary: ● arn:minio:replication::6593d572-4dc3-4bb9-8d90-7f79cc612f01:data Status: Ongoing Replication Status | Size (Bytes) | Count Replicated | 2.3 GiB | 18 Failed | 0 B | 0 The :guilabel:`Status` updates to ``Completed`` once the resynchronization process completes. 4) Next Steps ~~~~~~~~~~~~~ - If the ``TARGET`` bucket damage extends to replication rules, you must recreate those rules to match the previous replication configuration. See :ref:`minio-bucket-replication-serverside-twoway` for additional guidance. - Perform basic validation that all buckets in the replication configuration show similar results for commands such as :mc:`mc ls` and :mc:`mc stat`. - After restoring any replication rules and verifying replication between sites, you can configure the reverse proxy, load balancer, or other network control plane managing connections to resume sending traffic to the resynchronized deployment.