---
title: Volumes
description: Attach a disk to a service so files survive deploys and restarts, and grow it when it fills up.
section: Services
order: 8
---

A volume is a disk mounted into a service that keeps its data through every deploy and restart. Use one for uploads, SQLite files and anything else your code writes to disk and needs to keep. For relational data, a [PostgreSQL](/docs/postgresql) database is usually the better choice.

## Add a volume

Open the service's **Settings**, find **Volume** and choose **Add a volume**. Enter the **Mount path**, which defaults to `/data`, pick a **Size** and choose **Add volume**. Dekka creates the disk straight away, without going through staged changes, and the volume moves from **Creating** to **Attached**.

```bash tab="cURL"
curl https://api.dekka.cloud/v1/resources/$SERVICE_ID/volume \
  -H "Authorization: Bearer $DEKKA_API_KEY" \
  --json '{ "mount_path": "/data", "size_gb": 5 }'
```

A service can have one volume, between 1 and 1024 GB, and a service with a volume runs a single replica, so set **Replicas** to 1 first. Forking an environment gives each copied service a new, empty volume of the same size.

## Grow a volume

Choose a larger size under **Grow to** and choose **Grow**. Volumes can grow but never shrink. If growing fails, the volume stays at its old size with its data intact.

## Remove a volume

Choose **Remove**. This deletes the volume and everything on it, and can't be undone.

## How much volume space do I get?

Volumes in an organisation share one allowance: 1 GB on Free, 20 GB on Starter and 100 GB on Growth. Dekka measures the size of each volume every hour as `volume_gb_hours`, and each plan includes its allowance for a 730-hour month. See [Plans, billing and usage](/docs/billing).

## Back up a volume

Dekka backs up a volume only when you choose **Back up now** in the **Volume** section, or call `POST /v1/volumes/{id}/backups`, and keeps each backup for 30 days. During the pilot the backup is kept on the same server as the volume, so keep your own copy of anything you can't lose. [Backups](/docs/backups) covers restoring one.