diff --git a/ansible/roles/nextcloud/tasks/main.yml b/ansible/roles/nextcloud/tasks/main.yml
index ea8931c..279a0bb 100644
--- a/ansible/roles/nextcloud/tasks/main.yml
+++ b/ansible/roles/nextcloud/tasks/main.yml
@@ -1,6 +1,12 @@
 ---
 # Main tasks for Nextcloud deployment
 
+- name: Include volume mounting tasks
+  include_tasks: mount-volume.yml
+  tags:
+    - nextcloud
+    - volume
+
 - name: Include Docker deployment tasks
   include_tasks: docker.yml
   tags:
diff --git a/ansible/roles/nextcloud/tasks/mount-volume.yml b/ansible/roles/nextcloud/tasks/mount-volume.yml
new file mode 100644
index 0000000..e1c2479
--- /dev/null
+++ b/ansible/roles/nextcloud/tasks/mount-volume.yml
@@ -0,0 +1,74 @@
+---
+# Mount Hetzner Volume for Nextcloud Data Storage
+#
+# This task file handles mounting the Hetzner Volume that stores Nextcloud user data.
+# The volume is created and attached by OpenTofu, we just mount it here.
+
+- name: Wait for volume device to appear
+  wait_for:
+    path: /dev/disk/by-id/
+    timeout: 30
+  register: disk_ready
+
+- name: Find Nextcloud volume device
+  shell: |
+    ls -1 /dev/disk/by-id/scsi-0HC_Volume_* 2>/dev/null | grep -i "nextcloud-data-{{ client_name }}" | head -1
+  register: volume_device_result
+  changed_when: false
+  failed_when: volume_device_result.rc != 0
+
+- name: Set volume device fact
+  set_fact:
+    volume_device: "{{ volume_device_result.stdout }}"
+
+- name: Display found volume device
+  debug:
+    msg: "Found Nextcloud volume at: {{ volume_device }}"
+
+- name: Check if volume is already formatted
+  shell: |
+    blkid {{ volume_device }} | grep -q 'TYPE="ext4"'
+  register: volume_formatted
+  changed_when: false
+  failed_when: false
+
+- name: Format volume as ext4 if not formatted
+  filesystem:
+    fstype: ext4
+    dev: "{{ volume_device }}"
+  when: volume_formatted.rc != 0
+
+- name: Create mount point directory
+  file:
+    path: /mnt/nextcloud-data
+    state: directory
+    mode: '0755'
+
+- name: Mount Nextcloud data volume
+  mount:
+    path: /mnt/nextcloud-data
+    src: "{{ volume_device }}"
+    fstype: ext4
+    state: mounted
+    opts: defaults,discard
+  register: mount_result
+
+- name: Ensure mount persists across reboots
+  mount:
+    path: /mnt/nextcloud-data
+    src: "{{ volume_device }}"
+    fstype: ext4
+    state: present
+    opts: defaults,discard
+
+- name: Create Nextcloud data directory on volume
+  file:
+    path: /mnt/nextcloud-data/data
+    state: directory
+    owner: www-data
+    group: www-data
+    mode: '0750'
+
+- name: Display mount success
+  debug:
+    msg: "Nextcloud volume successfully mounted at /mnt/nextcloud-data"
diff --git a/ansible/roles/nextcloud/templates/docker-compose.nextcloud.yml.j2 b/ansible/roles/nextcloud/templates/docker-compose.nextcloud.yml.j2
index 1c7a216..04199e8 100644
--- a/ansible/roles/nextcloud/templates/docker-compose.nextcloud.yml.j2
+++ b/ansible/roles/nextcloud/templates/docker-compose.nextcloud.yml.j2
@@ -35,7 +35,8 @@ services:
       - nextcloud-db
       - nextcloud-redis
     volumes:
-      - nextcloud-data:/var/www/html
+      - nextcloud-app:/var/www/html
+      - /mnt/nextcloud-data/data:/var/www/html/data  # User data on Hetzner Volume
     entrypoint: /cron.sh
     networks:
       - nextcloud-internal
@@ -49,7 +50,8 @@ services:
       - nextcloud-db
       - nextcloud-redis
     volumes:
-      - nextcloud-data:/var/www/html
+      - nextcloud-app:/var/www/html
+      - /mnt/nextcloud-data/data:/var/www/html/data  # User data on Hetzner Volume
     environment:
       # Database configuration
       POSTGRES_HOST: {{ nextcloud_db_host }}
@@ -158,5 +160,6 @@ volumes:
     name: nextcloud-db-data
   nextcloud-redis-data:
     name: nextcloud-redis-data
-  nextcloud-data:
-    name: nextcloud-data
+  nextcloud-app:
+    name: nextcloud-app
+    # Note: nextcloud-data volume removed - user data now stored on Hetzner Volume at /mnt/nextcloud-data
diff --git a/docs/storage-architecture.md b/docs/storage-architecture.md
new file mode 100644
index 0000000..81c08a4
--- /dev/null
+++ b/docs/storage-architecture.md
@@ -0,0 +1,449 @@
+# Storage Architecture
+
+Comprehensive guide to storage architecture using Hetzner Volumes for Nextcloud data.
+
+## Overview
+
+The infrastructure uses **Hetzner Volumes** (block storage) for Nextcloud user data, separating application and data layers:
+
+- **Server local disk**: Operating system, Docker images, application code
+- **Hetzner Volume**: Nextcloud user files (/var/www/html/data)
+- **Docker volumes**: Database and Redis data (ephemeral, can be rebuilt)
+
+## Architecture Diagram
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│ Hetzner Cloud Server (cpx22)                                │
+│                                                               │
+│  ┌──────────────────────┐       ┌────────────────────────┐  │
+│  │ Local Disk (80 GB)   │       │ Hetzner Volume (100GB) │  │
+│  │                      │       │                        │  │
+│  │ - OS (Ubuntu 24.04)  │       │ Mounted at:            │  │
+│  │ - Docker images      │       │ /mnt/nextcloud-data    │  │
+│  │ - Application code   │       │                        │  │
+│  │ - Config files       │       │ Contains:              │  │
+│  │                      │       │ - Nextcloud user files │  │
+│  │ Docker volumes:      │       │ - Uploaded documents   │  │
+│  │ - postgres-db        │       │ - Photos, videos       │  │
+│  │ - redis-cache        │       │ - All user data        │  │
+│  │ - nextcloud-app      │       │                        │  │
+│  └──────────────────────┘       └────────────────────────┘  │
+│           │                                │                  │
+│           └────────────────────────────────┘                  │
+│                  Both accessible to                          │
+│                  Docker containers                           │
+└─────────────────────────────────────────────────────────────┘
+```
+
+## Benefits
+
+### 1. Data Independence
+- User data survives server rebuilds
+- Can detach volume from one server and attach to another
+- Easier disaster recovery
+
+### 2. Flexible Scaling
+- Resize storage without touching server
+- Pay only for storage you need
+- Start small (100 GB), grow as needed
+
+### 3. Better Separation
+- Application layer (ephemeral, can be rebuilt)
+- Data layer (persistent, backed up)
+- Clear distinction between code and content
+
+### 4. Simplified Backups
+- Snapshot volumes independently
+- Smaller, faster snapshots (only data, not OS)
+- Point-in-time recovery of user files
+
+### 5. Cost Optimization
+- Small clients: 50 GB (~€2.70/month)
+- Medium clients: 100 GB (~€5.40/month)
+- Large clients: 250+ GB (~€13.50+/month)
+- Only pay for what you use
+
+## Volume Specifications
+
+| Feature | Value |
+|---------|-------|
+| Minimum size | 10 GB |
+| Maximum size | 10 TB (10,000 GB) |
+| Pricing | €0.054/GB/month |
+| Performance | Fast NVMe SSD |
+| IOPS | High performance |
+| Filesystem | ext4 (pre-formatted) |
+| Snapshots | Supported |
+| Backups | Via Hetzner API |
+
+## How It Works
+
+### 1. OpenTofu Creates Volume
+
+When deploying a client:
+
+```hcl
+# tofu/volumes.tf
+resource "hcloud_volume" "nextcloud_data" {
+  for_each = var.clients
+
+  name     = "nextcloud-data-${each.key}"
+  size     = each.value.nextcloud_volume_size  # e.g., 100 GB
+  location = each.value.location
+  format   = "ext4"
+}
+
+resource "hcloud_volume_attachment" "nextcloud_data" {
+  for_each  = var.clients
+  volume_id = hcloud_volume.nextcloud_data[each.key].id
+  server_id = hcloud_server.client[each.key].id
+  automount = false
+}
+```
+
+### 2. Ansible Mounts Volume
+
+During deployment:
+
+```yaml
+# ansible/roles/nextcloud/tasks/mount-volume.yml
+- Find volume device at /dev/disk/by-id/scsi-0HC_Volume_*
+- Format as ext4 (if not already formatted)
+- Mount at /mnt/nextcloud-data
+- Create data directory with proper permissions
+```
+
+### 3. Docker Uses Mount
+
+Docker Compose configuration:
+
+```yaml
+services:
+  nextcloud:
+    volumes:
+      - nextcloud-app:/var/www/html           # Application code (local)
+      - /mnt/nextcloud-data/data:/var/www/html/data  # User data (volume)
+```
+
+## Directory Structure
+
+### On Server Local Disk
+
+```
+/var/lib/docker/volumes/
+├── nextcloud-app/           # Nextcloud application code
+├── nextcloud-db-data/       # PostgreSQL database
+└── nextcloud-redis-data/    # Redis cache
+
+/opt/docker/
+├── authentik/               # Authentik configuration
+├── nextcloud/               # Nextcloud docker-compose.yml
+└── traefik/                 # Traefik configuration
+```
+
+### On Hetzner Volume
+
+```
+/mnt/nextcloud-data/
+└── data/                    # Nextcloud user data directory
+    ├── admin/               # Admin user files
+    ├── user1/               # User 1 files
+    ├── user2/               # User 2 files
+    └── appdata_*/           # Application data
+```
+
+## Volume Sizing Guidelines
+
+### Small Clients (1-10 users)
+- **Starting size**: 50 GB
+- **Monthly cost**: ~€2.70
+- **Use case**: Personal use, small teams
+- **Growth**: +10 GB increments
+
+### Medium Clients (10-50 users)
+- **Starting size**: 100 GB
+- **Monthly cost**: ~€5.40
+- **Use case**: Small businesses, departments
+- **Growth**: +25 GB increments
+
+### Large Clients (50-200 users)
+- **Starting size**: 250 GB
+- **Monthly cost**: ~€13.50
+- **Use case**: Medium businesses
+- **Growth**: +50 GB increments
+
+### Enterprise Clients (200+ users)
+- **Starting size**: 500 GB+
+- **Monthly cost**: ~€27+
+- **Use case**: Large organizations
+- **Growth**: +100 GB increments
+
+**Pro tip**: Start conservative and grow as needed. Resizing is online and takes seconds.
+
+## Volume Operations
+
+### Resize Volume
+
+Increase volume size (cannot decrease):
+
+```bash
+./scripts/resize-client-volume.sh <client> <new_size_gb>
+```
+
+Example:
+```bash
+# Resize dev client from 100 GB to 200 GB
+./scripts/resize-client-volume.sh dev 200
+```
+
+The script will:
+1. Resize via Hetzner API
+2. Expand filesystem
+3. Verify new size
+4. Show cost increase
+
+**Note**: Resizing is **online** (no downtime) and **instant**.
+
+### Snapshot Volume
+
+Create a point-in-time snapshot:
+
+```bash
+# Via Hetzner Cloud Console
+# Or via API:
+hcloud volume create-snapshot nextcloud-data-dev \
+    --description "Before major update"
+```
+
+### Restore from Snapshot
+
+1. Create new volume from snapshot
+2. Attach to server
+3. Update mount in Ansible
+4. Restart Nextcloud containers
+
+### Detach and Move Volume
+
+Move data between servers:
+
+```bash
+# 1. Stop Nextcloud on old server
+ansible old-server -i hcloud.yml -m shell -a "docker stop nextcloud"
+
+# 2. Detach volume via Hetzner Console or API
+hcloud volume detach nextcloud-data-client1
+
+# 3. Attach to new server
+hcloud volume attach nextcloud-data-client1 --server new-server
+
+# 4. Mount on new server
+ansible new-server -i hcloud.yml -m shell -a "mount /dev/disk/by-id/scsi-0HC_Volume_* /mnt/nextcloud-data"
+
+# 5. Start Nextcloud
+ansible new-server -i hcloud.yml -m shell -a "docker start nextcloud"
+```
+
+## Backup Strategy
+
+### Option 1: Hetzner Volume Snapshots
+
+**Pros:**
+- Fast (incremental)
+- Integrated with Hetzner
+- Point-in-time recovery
+
+**Cons:**
+- Stored in same region
+- Not off-site
+
+**Implementation:**
+```bash
+# Daily snapshots via cron
+0 2 * * * hcloud volume create-snapshot nextcloud-data-prod \
+    --description "Daily backup $(date +%Y-%m-%d)"
+```
+
+### Option 2: Rsync to External Storage
+
+**Pros:**
+- Off-site backup
+- Full control
+- Can use any storage provider
+
+**Cons:**
+- Slower
+- More complex
+
+**Implementation:**
+```bash
+# Backup to external server
+ansible client -i hcloud.yml -m shell -a "\
+    rsync -av /mnt/nextcloud-data/data/ \
+    backup-server:/backups/client/nextcloud/"
+```
+
+### Option 3: Nextcloud Built-in Backup
+
+**Pros:**
+- Uses Nextcloud's own backup tools
+- Consistent with application state
+
+**Cons:**
+- Slower than volume snapshots
+
+**Implementation:**
+```bash
+# Using occ command
+docker exec -u www-data nextcloud php occ maintenance:mode --on
+rsync -av /mnt/nextcloud-data/ /backup/location/
+docker exec -u www-data nextcloud php occ maintenance:mode --off
+```
+
+## Performance Considerations
+
+### Hetzner Volume Performance
+
+| Metric | Specification |
+|--------|---------------|
+| Type | NVMe SSD |
+| IOPS | High (exact spec varies) |
+| Throughput | Fast sequential R/W |
+| Latency | Low (local to server) |
+
+### Optimization Tips
+
+1. **Use ext4 filesystem** (default, well-tested)
+2. **Enable discard** for SSD optimization (default in our setup)
+3. **Monitor I/O** with `iostat -x 1`
+4. **Check volume usage** regularly
+
+### Monitoring
+
+```bash
+# Check volume usage
+df -h /mnt/nextcloud-data
+
+# Check I/O stats
+iostat -x 1 /dev/disk/by-id/scsi-0HC_Volume_*
+
+# Check mount status
+mount | grep nextcloud-data
+```
+
+## Troubleshooting
+
+### Volume Not Mounting
+
+**Problem:** Volume doesn't mount after server restart
+
+**Solutions:**
+1. Check if volume is attached:
+   ```bash
+   lsblk
+   ls -la /dev/disk/by-id/scsi-0HC_Volume_*
+   ```
+
+2. Check fstab entry:
+   ```bash
+   cat /etc/fstab | grep nextcloud-data
+   ```
+
+3. Manually mount:
+   ```bash
+   mount /dev/disk/by-id/scsi-0HC_Volume_* /mnt/nextcloud-data
+   ```
+
+4. Re-run Ansible:
+   ```bash
+   ansible-playbook -i hcloud.yml playbooks/deploy.yml --limit client --tags volume
+   ```
+
+### Volume Full
+
+**Problem:** Nextcloud reports "not enough space"
+
+**Solutions:**
+1. Check usage:
+   ```bash
+   df -h /mnt/nextcloud-data
+   ```
+
+2. Resize volume:
+   ```bash
+   ./scripts/resize-client-volume.sh client 200
+   ```
+
+3. Clean up old files:
+   ```bash
+   docker exec -u www-data nextcloud php occ files:scan --all
+   docker exec -u www-data nextcloud php occ files:cleanup
+   ```
+
+### Permission Issues
+
+**Problem:** Nextcloud can't write to volume
+
+**Solutions:**
+1. Check ownership:
+   ```bash
+   ls -la /mnt/nextcloud-data/
+   ```
+
+2. Fix permissions:
+   ```bash
+   chown -R www-data:www-data /mnt/nextcloud-data/data
+   chmod -R 750 /mnt/nextcloud-data/data
+   ```
+
+3. Re-run mount tasks:
+   ```bash
+   ansible-playbook -i hcloud.yml playbooks/deploy.yml --limit client --tags volume
+   ```
+
+### Volume Detached Accidentally
+
+**Problem:** Volume was detached and lost mount
+
+**Solutions:**
+1. Re-attach via Hetzner Console or API
+2. Remount:
+   ```bash
+   ansible client -i hcloud.yml -m shell -a "\
+       mount /dev/disk/by-id/scsi-0HC_Volume_* /mnt/nextcloud-data"
+   ```
+3. Restart Nextcloud:
+   ```bash
+   docker restart nextcloud nextcloud-cron
+   ```
+
+## Cost Analysis
+
+### Example Scenarios
+
+**Scenario 1: 10 Clients, 100 GB each**
+- Volume cost: 10 × 100 GB × €0.054 = €54/month
+- Server cost: 10 × €7/month = €70/month
+- **Total**: €124/month
+
+**Scenario 2: 5 Small + 3 Medium + 2 Large**
+- Small (50 GB): 5 × €2.70 = €13.50
+- Medium (100 GB): 3 × €5.40 = €16.20
+- Large (250 GB): 2 × €13.50 = €27.00
+- **Volume total**: €56.70/month
+- Plus server costs
+
+**Cost Savings vs Local Disk:**
+- Can use smaller servers (cheaper compute)
+- Pay only for storage needed
+- Resize incrementally vs over-provisioning
+
+## Migration from Local Volumes
+
+See [volume-migration.md](volume-migration.md) for detailed migration procedures.
+
+## Related Documentation
+
+- [Volume Migration Guide](volume-migration.md) - Migrating existing clients
+- [Deployment Guide](deployment.md) - Full deployment with volumes
+- [Maintenance Tracking](maintenance-tracking.md) - Monitoring and updates
diff --git a/docs/volume-migration.md b/docs/volume-migration.md
new file mode 100644
index 0000000..8e0a416
--- /dev/null
+++ b/docs/volume-migration.md
@@ -0,0 +1,398 @@
+# Volume Migration Guide
+
+Step-by-step guide for migrating existing Nextcloud clients from local Docker volumes to Hetzner Volumes.
+
+## Overview
+
+This guide covers migrating an existing client (like `dev`) that currently stores Nextcloud data in a Docker volume to the new Hetzner Volume architecture.
+
+**Migration is SAFE and REVERSIBLE** - we keep the old data until verification is complete.
+
+## Prerequisites
+
+- Client currently deployed and running
+- SSH access to the server
+- Hetzner API token (`HCLOUD_TOKEN`)
+- SOPS age key for secrets (`SOPS_AGE_KEY_FILE`)
+- At least 30 minutes of maintenance window
+
+## Migration Steps
+
+### Phase 1: Preparation
+
+#### 1. Verify Current State
+
+```bash
+# Check client is running
+./scripts/client-status.sh dev
+
+# Check current data location
+cd ansible
+ansible dev -i hcloud.yml -m shell -a "docker inspect nextcloud | jq '.[0].Mounts'"
+```
+
+Expected output shows Docker volume:
+```json
+{
+  "Type": "volume",
+  "Name": "nextcloud-data",
+  "Source": "/var/lib/docker/volumes/nextcloud-data/_data",
+  "Destination": "/var/www/html"
+}
+```
+
+#### 2. Check Data Size
+
+```bash
+# Check how much data we're migrating
+ansible dev -i hcloud.yml -m shell -a "\
+    du -sh /var/lib/docker/volumes/nextcloud-data/_data/data"
+```
+
+Note the size - you'll need a volume at least this big (we recommend 2x for growth).
+
+#### 3. Notify Users
+
+⚠️ **Important**: Inform users that Nextcloud will be unavailable during migration (typically 10-30 minutes depending on data size).
+
+### Phase 2: Create and Attach Volume
+
+#### 4. Update OpenTofu Configuration
+
+Already done if you're following the issue #18 implementation:
+
+```hcl
+# tofu/terraform.tfvars
+clients = {
+  dev = {
+    # ... existing config ...
+    nextcloud_volume_size = 100  # Adjust based on current data size
+  }
+}
+```
+
+#### 5. Apply OpenTofu Changes
+
+```bash
+cd tofu
+
+# Review changes
+tofu plan
+
+# Apply - this creates the volume and attaches it
+tofu apply
+```
+
+Expected output:
+```
++ hcloud_volume.nextcloud_data["dev"]
++ hcloud_volume_attachment.nextcloud_data["dev"]
+```
+
+The volume is now attached to the server but not yet mounted.
+
+### Phase 3: Stop Services and Mount Volume
+
+#### 6. Enable Maintenance Mode
+
+```bash
+cd ansible
+
+# Enable Nextcloud maintenance mode
+ansible dev -i hcloud.yml -m shell -a "\
+    docker exec -u www-data nextcloud php occ maintenance:mode --on"
+```
+
+#### 7. Stop Nextcloud Containers
+
+```bash
+# Stop Nextcloud and cron (keep database and redis running)
+ansible dev -i hcloud.yml -m shell -a "\
+    docker stop nextcloud nextcloud-cron"
+```
+
+#### 8. Mount the Volume
+
+```bash
+# Run Ansible volume mounting tasks
+ansible-playbook -i hcloud.yml playbooks/deploy.yml \
+    --limit dev \
+    --tags volume
+```
+
+This will:
+- Find the volume device
+- Format as ext4 (if needed)
+- Mount at `/mnt/nextcloud-data`
+- Create data directory with correct permissions
+- Add to `/etc/fstab` for persistence
+
+#### 9. Verify Mount
+
+```bash
+# Check mount is successful
+ansible dev -i hcloud.yml -m shell -a "df -h /mnt/nextcloud-data"
+ansible dev -i hcloud.yml -m shell -a "ls -la /mnt/nextcloud-data"
+```
+
+### Phase 4: Migrate Data
+
+#### 10. Copy Data to Volume
+
+```bash
+# Copy all data from Docker volume to Hetzner Volume
+ansible dev -i hcloud.yml -m shell -a "\
+    rsync -avh --progress \
+    /var/lib/docker/volumes/nextcloud-data/_data/data/ \
+    /mnt/nextcloud-data/data/" -b
+```
+
+This will take some time depending on data size. Progress is shown.
+
+**Estimated times:**
+- 1 GB: ~30 seconds
+- 10 GB: ~5 minutes
+- 50 GB: ~20 minutes
+- 100 GB: ~40 minutes
+
+#### 11. Verify Data Copy
+
+```bash
+# Check data was copied
+ansible dev -i hcloud.yml -m shell -a "\
+    du -sh /mnt/nextcloud-data/data"
+
+# Verify file count matches
+ansible dev -i hcloud.yml -m shell -a "\
+    find /var/lib/docker/volumes/nextcloud-data/_data/data -type f | wc -l && \
+    find /mnt/nextcloud-data/data -type f | wc -l"
+```
+
+Both counts should match.
+
+#### 12. Fix Permissions
+
+```bash
+# Ensure correct ownership
+ansible dev -i hcloud.yml -m shell -a "\
+    chown -R www-data:www-data /mnt/nextcloud-data/data" -b
+```
+
+### Phase 5: Update Configuration and Restart
+
+#### 13. Update Docker Compose
+
+Already done if you're following the issue #18 implementation. The new template uses:
+
+```yaml
+volumes:
+  - /mnt/nextcloud-data/data:/var/www/html/data
+```
+
+#### 14. Deploy Updated Configuration
+
+```bash
+# Deploy updated docker-compose.yml
+ansible-playbook -i hcloud.yml playbooks/deploy.yml \
+    --limit dev \
+    --tags nextcloud,docker
+```
+
+This will:
+- Update docker-compose.yml
+- Restart Nextcloud with new volume mounts
+
+#### 15. Disable Maintenance Mode
+
+```bash
+# Turn off maintenance mode
+ansible dev -i hcloud.yml -m shell -a "\
+    docker exec -u www-data nextcloud php occ maintenance:mode --off"
+```
+
+### Phase 6: Verification
+
+#### 16. Test Nextcloud Access
+
+```bash
+# Check containers are running
+ansible dev -i hcloud.yml -m shell -a "docker ps | grep nextcloud"
+
+# Test HTTPS endpoint
+curl -I https://nextcloud.dev.vrije.cloud
+```
+
+Expected: HTTP 200 OK
+
+#### 17. Login and Verify Files
+
+1. Open https://nextcloud.dev.vrije.cloud in browser
+2. Login with admin credentials
+3. Navigate to Files
+4. Check that all files are visible
+5. Try uploading a new file
+6. Try downloading an existing file
+
+#### 18. Run Files Scan
+
+```bash
+# Scan all files to update Nextcloud's database
+ansible dev -i hcloud.yml -m shell -a "\
+    docker exec -u www-data nextcloud php occ files:scan --all"
+```
+
+#### 19. Check for Errors
+
+```bash
+# Check Nextcloud logs
+ansible dev -i hcloud.yml -m shell -a "\
+    docker logs nextcloud --tail 50"
+
+# Check for any errors in admin panel
+# Login → Settings → Administration → Logging
+```
+
+### Phase 7: Cleanup (Optional)
+
+⚠️ **Wait at least 24-48 hours before cleanup to ensure everything works!**
+
+#### 20. Remove Old Docker Volume
+
+After confirming everything works:
+
+```bash
+# Remove old Docker volume (THIS IS IRREVERSIBLE!)
+ansible dev -i hcloud.yml -m shell -a "\
+    docker volume rm nextcloud-data"
+```
+
+You'll get an error if any container is still using it (good safety check).
+
+## Rollback Procedure
+
+If something goes wrong, you can rollback:
+
+### Quick Rollback (During Migration)
+
+If you haven't removed the old Docker volume:
+
+```bash
+# 1. Stop containers
+ansible dev -i hcloud.yml -m shell -a "docker stop nextcloud nextcloud-cron"
+
+# 2. Revert docker-compose.yml to use old volume
+# (restore from git or manually edit)
+
+# 3. Restart containers
+ansible dev -i hcloud.yml -m shell -a "cd /opt/docker/nextcloud && docker-compose up -d"
+
+# 4. Disable maintenance mode
+ansible dev -i hcloud.yml -m shell -a "\
+    docker exec -u www-data nextcloud php occ maintenance:mode --off"
+```
+
+### Full Rollback (After Cleanup)
+
+If you've removed the old volume but have a backup:
+
+```bash
+# 1. Restore from backup to new volume
+# 2. Continue with Phase 5 (restart with new config)
+```
+
+## Verification Checklist
+
+After migration, verify:
+
+- [ ] Nextcloud web interface loads
+- [ ] Can login with existing credentials
+- [ ] All files and folders visible
+- [ ] Can upload new files
+- [ ] Can download existing files
+- [ ] Can edit files (if Collabora Online installed)
+- [ ] Sharing links still work
+- [ ] Mobile apps can sync
+- [ ] Desktop clients can sync
+- [ ] No errors in Nextcloud logs
+- [ ] No errors in admin panel
+- [ ] Volume is mounted in `/etc/fstab`
+- [ ] Volume mounts after server reboot
+
+## Common Issues
+
+### Issue: "Permission denied" errors
+
+**Cause:** Wrong ownership on volume
+
+**Fix:**
+```bash
+ansible dev -i hcloud.yml -m shell -a "\
+    chown -R www-data:www-data /mnt/nextcloud-data/data" -b
+```
+
+### Issue: "Volume not found" in Docker
+
+**Cause:** Docker compose still referencing old volume name
+
+**Fix:**
+```bash
+# Check docker-compose.yml has correct mount
+ansible dev -i hcloud.yml -m shell -a "cat /opt/docker/nextcloud/docker-compose.yml | grep mnt"
+
+# Should show: /mnt/nextcloud-data/data:/var/www/html/data
+```
+
+### Issue: Files missing after migration
+
+**Cause:** Incomplete rsync
+
+**Fix:**
+```bash
+# Re-run rsync (it will only copy missing files)
+ansible dev -i hcloud.yml -m shell -a "\
+    rsync -avh \
+    /var/lib/docker/volumes/nextcloud-data/_data/data/ \
+    /mnt/nextcloud-data/data/" -b
+```
+
+### Issue: Volume unmounted after reboot
+
+**Cause:** Not in `/etc/fstab`
+
+**Fix:**
+```bash
+# Re-run volume mounting tasks
+ansible-playbook -i hcloud.yml playbooks/deploy.yml --limit dev --tags volume
+```
+
+## Post-Migration Benefits
+
+After successful migration:
+
+- ✅ Can resize storage independently: `./scripts/resize-client-volume.sh dev 200`
+- ✅ Can snapshot data separately from system
+- ✅ Can move data to new server if needed
+- ✅ Better separation of application and data
+- ✅ Clearer backup strategy
+
+## Timeline Example
+
+Real-world timeline for 10 GB Nextcloud instance:
+
+| Step | Duration | Notes |
+|------|----------|-------|
+| Preparation | 5 min | Check status, plan |
+| Create volume (OpenTofu) | 2 min | Automated |
+| Stop services | 1 min | Quick |
+| Mount volume | 2 min | Ansible tasks |
+| Copy data (10 GB) | 5 min | Depends on size |
+| Update config | 2 min | Ansible deploy |
+| Restart services | 2 min | Docker restart |
+| Verification | 10 min | Manual testing |
+| **Total** | **~30 min** | Includes safety checks |
+
+## Related Documentation
+
+- [Storage Architecture](storage-architecture.md) - Understanding volumes
+- [Deployment Guide](deployment.md) - New deployments with volumes
+- [Client Registry](client-registry.md) - Track migration status
diff --git a/scripts/resize-client-volume.sh b/scripts/resize-client-volume.sh
new file mode 100755
index 0000000..cf0cfd1
--- /dev/null
+++ b/scripts/resize-client-volume.sh
@@ -0,0 +1,192 @@
+#!/usr/bin/env bash
+#
+# Resize a client's Nextcloud data volume
+#
+# Usage: ./scripts/resize-client-volume.sh <client_name> <new_size_gb>
+#
+# This script will:
+# 1. Resize the Hetzner Volume via API
+# 2. Expand the filesystem on the server
+# 3. Verify the new size
+#
+# Note: Volumes can only be increased in size, never decreased
+
+set -euo pipefail
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+BLUE='\033[0;34m'
+NC='\033[0m' # No Color
+
+# Script directory
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
+
+# Check arguments
+if [ $# -ne 2 ]; then
+    echo -e "${RED}Error: Client name and new size required${NC}"
+    echo "Usage: $0 <client_name> <new_size_gb>"
+    echo ""
+    echo "Example: $0 dev 200"
+    echo ""
+    echo "Note: You can only INCREASE volume size, never decrease"
+    exit 1
+fi
+
+CLIENT_NAME="$1"
+NEW_SIZE="$2"
+
+# Validate new size is a number
+if ! [[ "$NEW_SIZE" =~ ^[0-9]+$ ]]; then
+    echo -e "${RED}Error: Size must be a number${NC}"
+    exit 1
+fi
+
+# Check minimum size
+if [ "$NEW_SIZE" -lt 10 ]; then
+    echo -e "${RED}Error: Minimum volume size is 10 GB${NC}"
+    exit 1
+fi
+
+# Check maximum size
+if [ "$NEW_SIZE" -gt 10000 ]; then
+    echo -e "${RED}Error: Maximum volume size is 10,000 GB (10 TB)${NC}"
+    exit 1
+fi
+
+# Check required environment variables
+if [ -z "${HCLOUD_TOKEN:-}" ]; then
+    echo -e "${RED}Error: HCLOUD_TOKEN environment variable not set${NC}"
+    echo "Export your Hetzner Cloud API token:"
+    echo "  export HCLOUD_TOKEN='your-token-here'"
+    exit 1
+fi
+
+echo -e "${BLUE}========================================${NC}"
+echo -e "${BLUE}Resizing Nextcloud Volume${NC}"
+echo -e "${BLUE}========================================${NC}"
+echo ""
+echo "Client: $CLIENT_NAME"
+echo "New size: ${NEW_SIZE} GB"
+echo ""
+
+# Step 1: Get volume ID from Hetzner API
+echo -e "${YELLOW}[1/4] Looking up volume...${NC}"
+
+VOLUME_NAME="nextcloud-data-${CLIENT_NAME}"
+
+# Get volume info
+VOLUME_INFO=$(curl -s -H "Authorization: Bearer $HCLOUD_TOKEN" \
+    "https://api.hetzner.cloud/v1/volumes?name=$VOLUME_NAME")
+
+VOLUME_ID=$(echo "$VOLUME_INFO" | jq -r '.volumes[0].id // empty')
+CURRENT_SIZE=$(echo "$VOLUME_INFO" | jq -r '.volumes[0].size // empty')
+
+if [ -z "$VOLUME_ID" ] || [ "$VOLUME_ID" = "null" ]; then
+    echo -e "${RED}Error: Volume '$VOLUME_NAME' not found${NC}"
+    echo "Make sure the client exists and has been deployed with volume support"
+    exit 1
+fi
+
+echo "Volume ID: $VOLUME_ID"
+echo "Current size: ${CURRENT_SIZE} GB"
+echo ""
+
+# Check if new size is larger
+if [ "$NEW_SIZE" -le "$CURRENT_SIZE" ]; then
+    echo -e "${RED}Error: New size ($NEW_SIZE GB) must be larger than current size ($CURRENT_SIZE GB)${NC}"
+    echo "Volumes can only be increased in size, never decreased"
+    exit 1
+fi
+
+# Calculate cost increase
+COST_INCREASE=$(echo "scale=2; ($NEW_SIZE - $CURRENT_SIZE) * 0.054" | bc)
+
+echo -e "${YELLOW}Warning: This will increase monthly costs by approximately €${COST_INCREASE}${NC}"
+echo ""
+read -p "Continue with resize? (yes/no): " confirm
+
+if [ "$confirm" != "yes" ]; then
+    echo "Resize cancelled"
+    exit 0
+fi
+
+echo ""
+
+# Step 2: Resize volume via API
+echo -e "${YELLOW}[2/4] Resizing volume via Hetzner API...${NC}"
+
+RESIZE_RESULT=$(curl -s -X POST \
+    -H "Authorization: Bearer $HCLOUD_TOKEN" \
+    -H "Content-Type: application/json" \
+    -d "{\"size\": $NEW_SIZE}" \
+    "https://api.hetzner.cloud/v1/volumes/$VOLUME_ID/actions/resize")
+
+ACTION_ID=$(echo "$RESIZE_RESULT" | jq -r '.action.id // empty')
+
+if [ -z "$ACTION_ID" ] || [ "$ACTION_ID" = "null" ]; then
+    echo -e "${RED}Error: Failed to resize volume${NC}"
+    echo "$RESIZE_RESULT" | jq .
+    exit 1
+fi
+
+# Wait for resize action to complete
+echo "Waiting for resize action to complete..."
+while true; do
+    ACTION_STATUS=$(curl -s -H "Authorization: Bearer $HCLOUD_TOKEN" \
+        "https://api.hetzner.cloud/v1/volumes/actions/$ACTION_ID" | jq -r '.action.status')
+
+    if [ "$ACTION_STATUS" = "success" ]; then
+        break
+    elif [ "$ACTION_STATUS" = "error" ]; then
+        echo -e "${RED}Error: Resize action failed${NC}"
+        exit 1
+    fi
+
+    sleep 2
+done
+
+echo -e "${GREEN}✓ Volume resized${NC}"
+echo ""
+
+# Step 3: Expand filesystem on the server
+echo -e "${YELLOW}[3/4] Expanding filesystem on server...${NC}"
+
+cd "$PROJECT_ROOT/ansible"
+
+# Find the device
+DEVICE_CMD="ls -1 /dev/disk/by-id/scsi-0HC_Volume_* 2>/dev/null | grep -i 'nextcloud-data-${CLIENT_NAME}' | head -1"
+DEVICE=$(~/.local/bin/ansible -i hcloud.yml "$CLIENT_NAME" -m shell -a "$DEVICE_CMD" -o 2>/dev/null | tail -1 | awk '{print $NF}')
+
+if [ -z "$DEVICE" ]; then
+    echo -e "${RED}Error: Could not find volume device on server${NC}"
+    exit 1
+fi
+
+echo "Device: $DEVICE"
+
+# Resize filesystem
+~/.local/bin/ansible -i hcloud.yml "$CLIENT_NAME" -m shell -a "resize2fs $DEVICE" -b
+
+echo -e "${GREEN}✓ Filesystem expanded${NC}"
+echo ""
+
+# Step 4: Verify new size
+echo -e "${YELLOW}[4/4] Verifying new size...${NC}"
+
+DF_OUTPUT=$(~/.local/bin/ansible -i hcloud.yml "$CLIENT_NAME" -m shell -a "df -h /mnt/nextcloud-data" -o 2>/dev/null | tail -1)
+
+echo "$DF_OUTPUT"
+echo ""
+
+echo -e "${GREEN}========================================${NC}"
+echo -e "${GREEN}✓ Resize complete!${NC}"
+echo -e "${GREEN}========================================${NC}"
+echo ""
+echo "Volume resized from ${CURRENT_SIZE} GB to ${NEW_SIZE} GB"
+echo "Additional monthly cost: €${COST_INCREASE}"
+echo ""
+echo "The new storage is immediately available to Nextcloud."
+echo ""
diff --git a/tofu/variables.tf b/tofu/variables.tf
index 2906a44..6c4d85c 100644
--- a/tofu/variables.tf
+++ b/tofu/variables.tf
@@ -26,10 +26,11 @@ variable "base_domain" {
 variable "clients" {
   description = "Map of client configurations"
   type = map(object({
-    server_type = string       # e.g., "cx22" (2 vCPU, 4 GB RAM)
-    location    = string       # e.g., "fsn1" (Falkenstein), "nbg1" (Nuremberg), "hel1" (Helsinki)
-    subdomain   = string       # e.g., "alpha" for alpha.platform.nl
-    apps        = list(string) # e.g., ["zitadel", "nextcloud"]
+    server_type            = string       # e.g., "cx22" (2 vCPU, 4 GB RAM)
+    location               = string       # e.g., "fsn1" (Falkenstein), "nbg1" (Nuremberg), "hel1" (Helsinki)
+    subdomain              = string       # e.g., "alpha" for alpha.platform.nl
+    apps                   = list(string) # e.g., ["zitadel", "nextcloud"]
+    nextcloud_volume_size  = number       # Size in GB for Nextcloud data volume (min 10, max 10000)
   }))
   default = {}
 }
diff --git a/tofu/volumes.tf b/tofu/volumes.tf
new file mode 100644
index 0000000..a742f68
--- /dev/null
+++ b/tofu/volumes.tf
@@ -0,0 +1,31 @@
+# Hetzner Volumes for Nextcloud Data Storage
+#
+# Each client gets a dedicated volume for Nextcloud user data.
+# Volumes are independent from server instances, enabling:
+# - Independent storage scaling
+# - Easy data migration between servers
+# - Simpler backup/restore procedures
+# - Better separation of application and data
+
+resource "hcloud_volume" "nextcloud_data" {
+  for_each = var.clients
+
+  name     = "nextcloud-data-${each.key}"
+  size     = each.value.nextcloud_volume_size
+  location = each.value.location
+  format   = "ext4"
+
+  labels = {
+    client  = each.key
+    purpose = "nextcloud-data"
+    managed = "terraform"
+  }
+}
+
+resource "hcloud_volume_attachment" "nextcloud_data" {
+  for_each = var.clients
+
+  volume_id = hcloud_volume.nextcloud_data[each.key].id
+  server_id = hcloud_server.client[each.key].id
+  automount = false # We mount manually via Ansible for better control
+}