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External Storages

Backup & Restore (BR), TiDB Lighting, and Dumpling support reading and writing data on the local filesystem and on Amazon S3. BR also supports reading and writing data on the Google Cloud Storage (GCS). These are distinguished by the URL scheme in the --storage parameter passed into BR, in the -d parameter passed into TiDB Lightning, and in the --output (-o) parameter passed into Dumpling.

Schemes

The following services are supported:

ServiceSchemesExample URL
Local filesystem, distributed on every nodelocallocal:///path/to/dest/
Amazon S3 and compatible servicess3s3://bucket-name/prefix/of/dest/
Google Cloud Storage (GCS)gcs, gsgcs://bucket-name/prefix/of/dest/
Write to nowhere (for benchmarking only)noopnoop://

URL parameters

Cloud storages such as S3 and GCS sometimes require additional configuration for connection. You can specify parameters for such configuration. For example:

  • Use Dumpling to export data to S3:

    ./dumpling -u root -h 127.0.0.1 -P 3306 -B mydb -F 256MiB \
        -o 's3://my-bucket/sql-backup?region=us-west-2'
  • Use TiDB Lightning to import data from S3:

    ./tidb-lightning --tidb-port=4000 --pd-urls=127.0.0.1:2379 --backend=local --sorted-kv-dir=/tmp/sorted-kvs \
        -d 's3://my-bucket/sql-backup?region=us-west-2'
  • Use TiDB Lightning to import data from S3 (using the path style in the request mode):

    ./tidb-lightning --tidb-port=4000 --pd-urls=127.0.0.1:2379 --backend=local --sorted-kv-dir=/tmp/sorted-kvs \
        -d 's3://my-bucket/sql-backup?force-path-style=true&endpoint=http://10.154.10.132:8088'
  • Use BR to back up data to GCS:

    ./br backup full -u 127.0.0.1:2379 \
        -s 'gcs://bucket-name/prefix'

S3 URL parameters

URL parameterDescription
access-keyThe access key
secret-access-keyThe secret access key
regionService Region for Amazon S3 (default to us-east-1)
use-accelerate-endpointWhether to use the accelerate endpoint on Amazon S3 (default to false)
endpointURL of custom endpoint for S3-compatible services (for example, https://s3.example.com/)
force-path-styleUse path style access rather than virtual hosted style access (default to false)
storage-classStorage class of the uploaded objects (for example, STANDARD, STANDARD_IA)
sseServer-side encryption algorithm used to encrypt the upload (empty, AES256 or aws:kms)
sse-kms-key-idIf sse is set to aws:kms, specifies the KMS ID
aclCanned ACL of the uploaded objects (for example, private, authenticated-read)

Note:

It is not recommended to pass in the access key and secret access key directly in the storage URL, because these keys are logged in plain text. The migration tools try to infer these keys from the environment in the following order:

  1. $AWS_ACCESS_KEY_ID and $AWS_SECRET_ACCESS_KEY environment variables
  2. $AWS_ACCESS_KEY and $AWS_SECRET_KEY environment variables
  3. Shared credentials file on the tool node at the path specified by the $AWS_SHARED_CREDENTIALS_FILE environment variable
  4. Shared credentials file on the tool node at ~/.aws/credentials
  5. Current IAM role of the Amazon EC2 container
  6. Current IAM role of the Amazon ECS task

GCS URL parameters

URL parameterDescription
credentials-fileThe path to the credentials JSON file on the tool node
storage-classStorage class of the uploaded objects (for example, STANDARD, COLDLINE)
predefined-aclPredefined ACL of the uploaded objects (for example, private, project-private)

When credentials-file is not specified, the migration tool will try to infer the credentials from the environment, in the following order:

  1. Content of the file on the tool node at the path specified by the $GOOGLE_APPLICATION_CREDENTIALS environment variable
  2. Content of the file on the tool node at ~/.config/gcloud/application_default_credentials.json
  3. When running in GCE or GAE, the credentials fetched from the metadata server.

Command-line parameters

In addition to the URL parameters, BR and Dumpling also support specifying these configurations using command-line parameters. For example:

./dumpling -u root -h 127.0.0.1 -P 3306 -B mydb -F 256MiB \
    -o 's3://my-bucket/sql-backup' \
    --s3.region 'us-west-2'

If you have specified URL parameters and command-line parameters at the same time, the URL parameters are overwritten by the command-line parameters.

S3 command-line parameters

Command-line parameterDescription
--s3.regionAmazon S3's service region, which defaults to us-east-1.
--s3.endpointThe URL of custom endpoint for S3-compatible services. For example, https://s3.example.com/.
--s3.storage-classThe storage class of the upload object. For example, STANDARD and STANDARD_IA.
--s3.sseThe server-side encryption algorithm used to encrypt the upload. The value options are empty, AES256 and aws:kms.
--s3.sse-kms-key-idIf --s3.sse is configured as aws:kms, this parameter is used to specify the KMS ID.
--s3.aclThe canned ACL of the upload object. For example, private and authenticated-read.
--s3.providerThe type of the S3-compatible service. The supported types are aws, alibaba, ceph, netease and other.

GCS command-line parameters

Command-line parameterDescription
--gcs.credentials-fileThe path of the JSON-formatted credential on the tool node.
--gcs.storage-classThe storage type of the upload object, such as STANDARD and COLDLINE.
--gcs.predefined-aclThe pre-defined ACL of the upload object, such as private and project-private.

BR sending credentials to TiKV

By default, when using S3 and GCS destinations, BR will send the credentials to every TiKV nodes to reduce setup complexity.

However, this is unsuitable on cloud environment, where every node has their own role and permission. In such cases, you need to disable credentials sending with --send-credentials-to-tikv=false (or the short form -c=0):

./br backup full -c=0 -u pd-service:2379 -s 's3://bucket-name/prefix'

When using SQL statements to back up and restore data, you can add the SEND_CREDENTIALS_TO_TIKV = FALSE option:

BACKUP DATABASE * TO 's3://bucket-name/prefix' SEND_CREDENTIALS_TO_TIKV = FALSE;

This option is not supported in TiDB Lightning and Dumpling, because the two applications are currently standalone.