---
title: "Migrate to Thanos storage clients | Grafana Loki documentation"
description: "Migration guide for moving from existing storage clients to Thanos storage clients."
---

> For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt).

# Migrate to Thanos storage clients

Loki has object storage clients based on the [Thanos Object Storage Client Go module](https://github.com/thanos-io/objstore). These clients were added in Loki 3.4.

One of the reasons for making this change is to have a consistent storage configuration across Grafana Loki, Mimir and other telemetry databases from Grafana Labs. If you are already using Grafana Mimir or Pyroscope, you can reuse the storage configuration for setting up Loki.

Loki 4.0 uses the Thanos-based clients by default, because the `use_thanos_objstore` setting defaults to `true`. The legacy storage clients are deprecated. Use this guide to convert your storage configuration to the new format. If you are not ready to migrate, set `use_thanos_objstore` to `false` to keep using the legacy clients.

In Loki 3.4 and later 3.x releases, the Thanos-based clients are optional. To use them in those releases, set `use_thanos_objstore` to `true`.

> Note
> 
> The new storage configuration deviates from the existing format. The following sections describe the changes in detail for each provider. Refer to the [Thanos storage configuration reference](/docs/loki/next/configure/#thanos_object_store_config) to view the complete list of supported storage providers and their configuration options.

### Configure the new storage clients

1. Configure your object storage under `storage_config.object_store`. When the Thanos-based clients are in use, Loki reads this section instead of the legacy storage configuration. In Loki 3.x, you must also set `use_thanos_objstore` to `true` in the `storage_config` section, or set the `-use-thanos-objstore` flag to `true`. The following examples set this option explicitly, which is also valid in Loki 4.0.
   
   YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```yaml
   # Uses the new storage clients for connecting to gcs backend
   storage_config:
     use_thanos_objstore: true # use the Thanos-based storage clients
     object_store:
       gcs:
         bucket_name: "example-bucket"
   ```
2. As an alternative, you can also configure the new clients in the common `storage` section if you prefer to use the `common` config section.
   
   YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```yaml
   storage_config:
      use_thanos_objstore: true # use the Thanos-based storage clients
   common:
     storage:
       object_store:
         gcs:
           bucket_name: "example-bucket"
   ```
3. Ruler storage should be configured under the `ruler_storage` section when using the new storage clients.
   
   YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```yaml
   storage_config:
      use_thanos_objstore: true # use the Thanos-based storage clients
   ruler_storage:
      backend: gcs
      gcs:
         bucket_name: "example-bucket"
   ```
4. If you are using `store.object-prefix` flag or the corresponding `object_prefix` YAML setting, you’ll need to update your configuration to use the new `object_store.storage-prefix` flag or the corresponding `storage_prefix` YAML setting.
   
   YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy
   
   ```yaml
   # Example configuration to prefix all objects with "prefix"
   storage_config:
      use_thanos_objstore: true # use the Thanos-based storage clients
      object_store:
         storage_prefix: "prefix"
   ```

### GCS Storage Migration

When migrating from the existing [Google Cloud Storage (GCS)](/docs/loki/next/configure/#gcs_storage_config) storage client to the new Thanos-based client, you’ll need to update your configuration parameters as follows:

Expand table

| Existing Parameter  | New Parameter       | Required Changes                                                                                                |
|---------------------|---------------------|-----------------------------------------------------------------------------------------------------------------|
| `bucket_name`       | `bucket_name`       | No changes required                                                                                             |
| `service_account`   | `service_account`   | No changes required                                                                                             |
| `chunk_buffer_size` | `chunk_buffer_size` | No changes required                                                                                             |
| `enable_retries`    | `max_retries`       | Replace `enable_retries` (bool) with `max_retries` (int). Set a value > 1 to enable retries, or 1 to disable |
| `request_timeout`   | Removed             | Remove parameter                                                                                                |
| `enable_opencensus` | Removed             | Remove parameter                                                                                                |
| `enable_http2`      | Removed             | Remove parameter                                                                                                |

**Example configuration migration (GCS):**

***Existing configuration:***

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
storage_config:
  gcs:
    bucket_name: example-bucket
    chunk_buffer_size: 10MB
    enable_retries: true
```

***New configuration*** (Thanos-based):

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
storage_config:
  use_thanos_objstore: true
  object_store:
    gcs:
      bucket_name: example-bucket
      chunk_buffer_size: 10MB
      max_retries: 5
```

### Amazon S3 Storage Migration

When migrating from the existing [Amazon S3](/docs/loki/next/configure/#aws_storage_config) storage client to the new Thanos-based client, update or remove parameters as follows:

Expand table

| Existing Parameter  | New Parameter       | Required Changes                                                                                                                            |
|---------------------|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------|
| `bucket_names`      | `bucket_name`       | Rename this parameter. If you previously used multiple buckets, you must consolidate to a single bucket (Thanos supports only one).         |
| `endpoint`          | `endpoint`          | No changes required.                                                                                                                        |
| `region`            | `region`            | No changes required.                                                                                                                        |
| `access_key_id`     | `access_key_id`     | No changes required.                                                                                                                        |
| `secret_access_key` | `secret_access_key` | No changes required.                                                                                                                        |
| `session_token`     | `session_token`     | No changes required.                                                                                                                        |
| `insecure`          | `insecure`          | No changes required.                                                                                                                        |
| `disable_dualstack` | `dualstack_enabled` | Renamed and inverted. If you had `disable_dualstack: false`, set `dualstack_enabled: true`.                                                 |
| `storage_class`     | `storage_class`     | No changes required.                                                                                                                        |
| `s3`                | Removed             | Remove or replace with `endpoint` if you used the URL-based setup.                                                                          |
| `S3ForcePathStyle`  | Removed or replaced | If you need path-based addressing, set `bucket_lookup_type: path` in the new config. Otherwise, remove it.                                  |
| `signature_version` | Removed             | Remove parameter. Thanos always uses Signature Version 4 (V4).                                                                              |
| `http_config`       | `http`              | Move subfields (such as timeouts, CA file, etc.) into the `http:` block in the Thanos configuration.                                        |
| `sse`               | `sse`               | Migrate any SSE settings (e.g., `type`, `kms_key_id`) into the `sse:` block in the Thanos configuration.                                    |
| `backoff_config`    | `max_retries`       | Replace the advanced backoff settings with a single integer (`max_retries`). Set to 1 to disable retries, or a higher value to enable them. |

**Example configuration migration (S3):**

***Existing configuration***

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
storage_config:
  aws:
    bucket_names: my-bucket1,my-bucket2   # multiple buckets no longer supported
    endpoint: s3.amazonaws.com
    region: us-west-2
    access_key_id: example-key
    secret_access_key: example-secret
    signature_version: v4
    disable_dualstack: true
    storage_class: STANDARD
    http_config:
      timeout: 1m
      insecure_skip_verify: false
    # ...
    backoff_config:
      max_retries: 5
    sse:
      type: SSE-KMS
      kms_key_id: mySSEKey
```

***New configuration** (Thanos-based)*

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
storage_config:
  use_thanos_objstore: true
  object_store:
    s3:
      bucket_name: my-bucket1                       # single bucket
      endpoint: s3.amazonaws.com
      region: us-west-2
      access_key_id: example-key
      secret_access_key: example-secret
      dualstack_enabled: false                        # was disable_dualstack: true
      storage_class: STANDARD
      max_retries: 5
      http:
        insecure_skip_verify: false
      sse:
        type: SSE-KMS
        kms_key_id: mySSEKey
```

For more advanced configuration options (such as `list_objects_version`, `bucket_lookup_type`, etc.), see the [Thanos S3 configuration reference](/docs/loki/next/configure/#thanos_object_store_config).

### Azure Storage Migration

When migrating from the existing [Azure](/docs/loki/next/configure/#azure_storage_config) storage client to the new Thanos-based client, no changes are required if you are using the following parameters:

Expand table

| Existing Parameter  | New Parameter       | Required Changes    |
|---------------------|---------------------|---------------------|
| `account_name`      | `account_name`      | No changes required |
| `account_key`       | `account_key`       | No changes required |
| `container_name`    | `container_name`    | No changes required |
| `endpoint_suffix`   | `endpoint_suffix`   | No changes required |
| `user_assigned_id`  | `user_assigned_id`  | No changes required |
| `connection_string` | `connection_string` | No changes required |
| `max_retries`       | `max_retries`       | No changes required |
| `chunk_delimiter`   | `chunk_delimiter`   | No changes required |

If you are using an authentication method other than storage account key or user-assigned managed identity, you’ll have to pass the necessary credentials using environment variables. For more details, refer to [Azure Identity Client Module for Go](https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azidentity).

### Filesystem Storage Migration

When migrating from the existing [Filesystem storage](/docs/loki/next/configure/#local_storage_config) client to the new Thanos-based client, update or remove parameters as follows:

Expand table

| Existing Parameter | New Parameter | Required Changes             |
|--------------------|---------------|------------------------------|
| `directory`        | `dir`         | Rename `directory` to `dir`. |

**Example configuration migration (Filesystem):**

***Existing configuration** (`FSConfig`)*

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
storage_config:
  filesystem:
    directory: /var/loki/chunks
```

***New configuration** (Thanos-based)*

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
storage_config:
  use_thanos_objstore: true
  object_store:
    filesystem:
      dir: /var/loki/chunks
```

> Note
> 
> For providers not listed here, refer to the [Thanos storage configuration reference](/docs/loki/next/configure/#thanos_object_store_config).