# Data Entity Attachments

Operators and users can attach **files and links** to any data entity to carry additional context — runbook PDFs, sample CSVs, dashboard screenshots, links to internal wikis, ticketing references. Attachments live alongside the entity's metadata and persist across re-ingests, behaving similarly to attachments on a Jira ticket.

{% hint style="danger" %}
**The default `LOCAL` storage mode is ephemeral.** Files are written to a local container path that is wiped on any container or pod restart — routine deployment, node drain, crash, Kubernetes eviction. Use `REMOTE` (S3 / MinIO) storage for any deployment where users will actually upload attachments. See the [Attachment Storage Configuration](/configuration-and-deployment/odd-platform.md#attachment-storage-configuration) operator reference for the storage caveats and the `us-east-1` constraint on AWS S3.
{% endhint %}

## Attaching a file

**Step 1.** Open the **Overview tab** of any data entity and click the **Add attachment** icon:

<figure><img src="/files/6bVt4xFqa1p2on6bynFF" alt="" height="508" width="700"><figcaption></figcaption></figure>

**Step 2.** Drag-and-drop the file into the attachment window, or browse to select:

<figure><img src="/files/pV5KEW4k1D7PtZlMvPnU" alt="" height="524" width="700"><figcaption></figcaption></figure>

There is no restriction on file type — images, CSVs, PDFs, TXT files, and any other format are accepted. The single restriction is **file size**, which is capped at `attachment.max-file-size` megabytes (default `20`). Files larger than the cap are rejected by the upload API.

If the file exceeds the size cap or the operator prefers to reference an external location, attach a **link** instead (next section).

## Attaching a link

**Step 3.** To attach a link to a remotely-stored file (or any URL), insert the link and provide a customised display name. Multiple links can be added in one go via the **+ Add link** icon:

<figure><img src="/files/57oKIn1qAFvXofi0aoOR" alt="" height="517" width="700"><figcaption></figcaption></figure>

Once saved, the file and the link both appear on the entity's Attachments list:

<figure><img src="/files/gRwDzOMhsuu0m3qFvMrT" alt="" height="464" width="700"><figcaption></figcaption></figure>

A single data entity can carry **multiple files and multiple links** — the platform does not cap the count.

## Editing and deleting attachments

Editing and deleting attachments — files and links alike — is performed by clicking the per-attachment icons next to each row:

<figure><img src="/files/OCD1qWQ8al1DTBQGOC1f" alt="" height="183" width="700"><figcaption></figcaption></figure>

## Storage backend (operator-configurable)

The platform supports two storage backends for the file (not the link) attachments:

* **`LOCAL`** *(default)* — files written to a local filesystem path inside the platform container. Suitable only for single-host evaluations and local development; **ephemeral on container restart**.
* **`REMOTE`** — S3-compatible object storage (AWS S3, MinIO, etc.). Required for production deployments. Configured via `attachment.storage`, `attachment.remote.url`, `attachment.remote.access-key`, `attachment.remote.secret-key`, `attachment.remote.bucket`.

The full operator-side reference (every key, the `us-east-1` AWS S3 constraint, the in-memory-buffer ceiling on `spring.codec.max-in-memory-size`) lives at [Configure ODD Platform → Attachment Storage Configuration](/configuration-and-deployment/odd-platform.md#attachment-storage-configuration). The hint at the top of this page is the operator-relevant summary; the configuration reference is authoritative.

<figure><img src="/files/eeDVh9RfxfWdLt51alRI" alt="" height="247" width="700"><figcaption></figcaption></figure>

## RBAC

Adding, deleting, and managing attachments on a data entity is gated by the `DATA_ENTITY_ATTACHMENT_MANAGE` permission. See [Permissions](/configuration-and-deployment/enable-security/authorization/permissions.md) for the full list and how to compose roles around it.

## Where to next

* [Configure ODD Platform → Attachment Storage Configuration](/configuration-and-deployment/odd-platform.md#attachment-storage-configuration) — the operator reference for the storage backend, including the LOCAL-is-ephemeral warning and the REMOTE caveats.
* [Permissions](/configuration-and-deployment/enable-security/authorization/permissions.md) — the `DATA_ENTITY_ATTACHMENT_MANAGE` permission and other data-entity permissions.
* [Data Discovery overview](/features/data-discovery.md) — the bucket landing this page sits under.


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