> ## Documentation Index > Fetch the complete documentation index at: https://docs.e6data.com/llms.txt > Use this file to discover all available pages before exploring further. # File sources > file_sources ReferenceApplies to: Unified engine deployments `[[file_sources]]` ## Settings ### `file_sources` Lists the file locations that this process is explicitly configured to read. * **Default:** `[]` * **Type:** array > **Example** > > Add one `[[file_sources]]` entry for a local folder and another for an S3 root. An empty array adds no explicit source-root bindings. ### `root_url` Names the logical source root that a file-source binding covers. * **Default:** Set when used * **Type:** string > **Example** > > `"s3://sales-data/raw/"` covers that root. Bind it to bucket `sales-data` and the physical `raw` prefix. Keep the final slash. ### `storage.backend` Chooses the physical storage that serves this readable file-source root. * **Default:** Set when used * **Type:** choice: `Local`, `Gcs`, `Azure`, `S3` > **Example** > > Map an `s3://imports/` root to its S3 bucket, or map a local logical root to a directory. The root URL and storage prefix must point to the same source files. ## Local storage ### `storage.backend.Local.directory` Chooses the local folder used by this storage adapter. * **Default:** Set when used * **Type:** string > **Example** > > `"/var/lib/laminar/results"` stores files there. Another pod with the same path string sees the same files only if both use a shared mount. ## Google Cloud Storage ### `storage.backend.Gcs.bucket` Names the cloud bucket containing the files for this storage adapter. * **Default:** Set when used * **Type:** string > **Example** > > `"analytics-data"` selects that bucket. A separate prefix such as `results` chooses the folder-like location within it. ### `storage.backend.Gcs.credential_reference` Names the saved credential used to access this storage. * **Default:** `""` * **Type:** string > **Example** > > `"warehouse"` selects the credential named warehouse. An empty string asks the adapter to use the process’s cloud identity where that is supported. ## Azure Blob Storage ### `storage.backend.Azure.account` Names the Azure storage account containing the container. * **Default:** Set when used * **Type:** string > **Example** > > An account named `analyticsstore` and container `results` identify the Blob location used by this adapter. ### `storage.backend.Azure.container` Names the Azure Blob container used by this storage adapter. * **Default:** Set when used * **Type:** string > **Example** > > `"results"` selects that container within the configured account. A prefix can narrow the location further. ### `storage.backend.Azure.endpoint` Optionally changes the Azure Blob service address used by this storage connection. * **Default:** Unset * **Type:** string; optional > **Example** > > Use the address supplied by an emulator or another Azure cloud. Leave it unset for the normal Azure Blob endpoint for the configured account. ### `storage.backend.Azure.allow_http` Chooses whether this storage adapter accepts an HTTP endpoint without HTTPS. * **Default:** `false` * **Type:** boolean > **Example** > > Set it to true for a local emulator served over HTTP. It does not change the endpoint URL by itself. ### `storage.backend.Azure.credential_reference` Names the saved credential used to access this storage. * **Default:** `""` * **Type:** string > **Example** > > `"warehouse"` selects the credential named warehouse. An empty string asks the adapter to use the process’s cloud identity where that is supported. ### `storage.backend.Azure.token_scope` Optionally selects the Azure token audience used for a cloud-specific storage endpoint. * **Default:** Unset * **Type:** string; optional > **Example** > > Use the scope required by your Azure cloud when the standard public-cloud audience does not apply. ## S3 storage ### `storage.backend.S3.bucket` Names the cloud bucket containing the files for this storage adapter. * **Default:** Set when used * **Type:** string > **Example** > > `"analytics-data"` selects that bucket. A separate prefix such as `results` chooses the folder-like location within it. ### `storage.backend.S3.region` Chooses the AWS Region used by this connection. * **Default:** Set when used * **Type:** string > **Example** > > `"us-east-1"` directs requests to that Region. Use the Region containing your bucket or Lambda function. ### `storage.backend.S3.endpoint` Optionally sends S3 requests to a custom S3-compatible service instead of the normal AWS endpoint. * **Default:** Unset * **Type:** string; optional > **Example** > > For a local object store, use `"http://object-store:9000"` and enable allow\_http. Omit the endpoint to use the standard AWS S3 service for the configured Region. ### `storage.backend.S3.allow_http` Chooses whether this storage adapter accepts an HTTP endpoint without HTTPS. * **Default:** `false` * **Type:** boolean > **Example** > > Set it to true for a local emulator served over HTTP. It does not change the endpoint URL by itself. ### `storage.backend.S3.credential_reference` Names the saved credential used to access this storage. * **Default:** `""` * **Type:** string > **Example** > > `"warehouse"` selects the credential named warehouse. An empty string asks the adapter to use the process’s cloud identity where that is supported. ## Transfer options ### `storage.options.prefix` Chooses the object-key prefix under the selected bucket or directory. * **Default:** Set when used * **Type:** string > **Example** > > With bucket `analytics-data` and prefix `results`, result objects are stored under `results/`. Changing the prefix points to a different location. ### `storage.options.part_bytes` Sets the amount of data in a storage transfer part. * **Default:** Set when used * **Type:** integer (bytes); positive > **Example** > > `8388608` chooses 8 MiB transfer parts. It does not mean the engine writes 8 MiB Parquet files. ## Choosing a backend A backend is selected by its table name, for example `[table_storage.backend.S3]`. Use only one variant for each backend. `endpoint` is optional for AWS S3; omit it for the standard service endpoint. For Azure, `token_scope` selects the cloud-specific token scope when required. 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