Doc: update docs update tmpfs

FAQ.md

@@ -507,3 +507,40 @@ Thats it, the `main.yml` will now disable the docker/github container registries
 naming, your container name will be named `REGISTRY/ytptube` and the tags will be the same as the ones used in the github registry.
 
 Unfortunately, the `native-builder.yml` workflow doesn't support self-hosted repositories at the moment.
+
+# Getting No space left on device error
+
+If you encounter this error: `OSError: [Errno 28] No space left on device` This indicates that either 
+the `/tmp` or `/downloads` directory has run out of available space.
+
+This issue commonly occurs when:
+
+- `/tmp` is mounted as `tmpfs` (memory-based storage)
+- Your system has limited RAM
+- You're downloading large video files
+
+Since videos are temporarily stored in `/tmp` before being moved to the final download location, memory-based storage 
+may be insufficient for large downloads.
+
+To fix the issue, modify your `compose.yaml` to use a disk-based directory for temporary files:
+
+```yaml
+services:
+  ytptube:
+    user: "${UID:-1000}:${UID:-1000}"
+    image: ghcr.io/arabcoders/ytptube:latest
+    container_name: ytptube
+    restart: unless-stopped
+    ports:
+      - "8081:8081"
+    volumes:
+      - ./config:/config:rw
+      - ./downloads:/downloads/local:rw
+      - ./temp:/tmp:rw
+```
+
+> [!NOTE]
+> Replace the `tmpfs` mount with a local directory volume (`./temp:/tmp:rw`). This allows temporary files to use disk space instead of RAM.
+
+After making the changes, restart your container. This should resolve the "No space left on device" 
+error during download.

README.md

@@ -77,6 +77,7 @@ services:
 
 > [!IMPORTANT]
 > Make sure to change the `user` line to match your user id and group id
+> If you have low RAM, remove the `tmpfs` and mount a disk-based directory to `/tmp` instead. See [FAQ](FAQ.md#getting-no-space-left-on-device-error) for more information.
 
 ```bash
 $ mkdir -p ./{config,downloads} && docker compose -f compose.yaml up -d