Restore Data from GCS

This document describes how to restore the TiDB cluster data backed up using TiDB Operator on Kubernetes.

The restore method described in this document is implemented based on CustomResourceDefinition (CRD) in TiDB Operator v1.1 or later versions. For the underlying implementation, TiDB Lightning TiDB-backend is used to perform the restore.

TiDB Lightning is a tool used for fast full import of large amounts of data into a TiDB cluster. It reads data from local disks, Google Cloud Storage (GCS) or Amazon S3. TiDB Lightning supports three backends: Importer-backend, Local-backend, and TiDB-backend. In this document, TiDB-backend is used. For the differences of these backends and how to choose backends, see TiDB Lightning Backends. To import data using Importer-backend or Local-backend, see Import Data.

This document shows an example in which the backup data stored in the specified path on GCS is restored to the TiDB cluster.

Usage scenarios

You can use the restore solution introduced in this document if you need to export the backup data from GCS to a TiDB cluster, with the following requirements:

To restore data with lower resource usage and lower network bandwidth usage. A restore speed of 50 GB/h is acceptable.
To import data into the cluster with ACID compliance.
The TiDB cluster can still provide services during the restore process.

Prerequisites

Before you perform the data restore, you need to prepare the restore environment and get the required database account privileges.

Prepare the restore environment

Download backup-rbac.yaml and execute the following command to create the role-based access control (RBAC) resources in the test2 namespace:
```
kubectl apply -f backup-rbac.yaml -n test2
```
Grant permissions to the remote storage.
Refer to GCS account permissions.

Create the restore-demo2-tidb-secret secret which stores the root account and password needed to access the TiDB cluster:

kubectl create secret generic restore-demo2-tidb-secret --from-literal=user=root --from-literal=password=${password} --namespace=test2

Get the required database account privileges

Before you use TiDB Lightning to restore the backup data in GCS to the TiDB cluster, make sure that you have the following database account privileges:

Privileges	Scope
SELECT	Tables
INSERT	Tables
UPDATE	Tables
DELETE	Tables
CREATE	Databases, tables
DROP	Databases, tables
ALTER	Tables

Restore process

Create the restore custom resource (CR) and restore the backup data to the TiDB cluster:

kubectl apply -f restore.yaml

The restore.yaml file has the following content:

---
apiVersion: pingcap.com/v1alpha1
kind: Restore
metadata:
  name: demo2-restore
  namespace: test2
spec:
  to:
    host: ${tidb_host}
    port: ${tidb_port}
    user: ${tidb_user}
    secretName: restore-demo2-tidb-secret
  gcs:
    projectId: ${project_id}
    secretName: gcs-secret
    path: gcs://${backup_path}
  # storageClassName: local-storage
  storageSize: 1Gi

The example above restores data from the spec.gcs.path path on GCS to the spec.to.host TiDB cluster. For more information about GCS configuration, refer to GCS fields.

For more information about the Restore CR fields, refer to Restore CR fields.

After creating the Restore CR, execute the following command to check the restore status:
```
kubectl get rt -n test2 -owide
```

Note

TiDB Operator creates a PVC for data recovery. The backup data is downloaded from the remote storage to the PV first, and then restored. If you want to delete this PVC after the recovery is completed, you can refer to Delete Resource to delete the recovery Pod first, and then delete the PVC.

Troubleshooting

If you encounter any problem during the restore process, refer to Common Deployment Failures.