diff --git a/backend/routers/system.py b/backend/routers/system.py
index 7ffdb11..0d9c3aa 100644
--- a/backend/routers/system.py
+++ b/backend/routers/system.py
@@ -168,7 +168,16 @@ async def get_network_traffic():
     return result
 
 
-# ============== DISK I/O ==============
+# ============== DISK USAGE + I/O ==============
+
+@router.get("/disk-usage")
+async def get_disk_usage():
+    """Get filesystem disk usage from df (public)"""
+    result = system_info.get_disk_usage()
+    if "error" in result:
+        raise HTTPException(status_code=500, detail=result["error"])
+    return result
+
 
 @router.get("/diskio")
 async def get_diskio():
diff --git a/backend/services/system_info.py b/backend/services/system_info.py
index e87271b..763b912 100644
--- a/backend/services/system_info.py
+++ b/backend/services/system_info.py
@@ -429,6 +429,42 @@ def get_all_units() -> Dict[str, Any]:
         return {"error": str(e)}
 
 
+def get_disk_usage() -> Dict[str, Any]:
+    try:
+        result = subprocess.run(
+            ["/usr/bin/df", "-P", "-x", "tmpfs", "-x", "devtmpfs", "-x", "squashfs", "-x", "overlay"],
+            capture_output=True, text=True, timeout=5
+        )
+        if result.returncode != 0:
+            return {"error": result.stderr}
+
+        filesystems = []
+        for line in result.stdout.strip().split("\n")[1:]:
+            parts = line.split()
+            if len(parts) < 6:
+                continue
+            try:
+                total = int(parts[1]) * 1024
+                used = int(parts[2]) * 1024
+                available = int(parts[3]) * 1024
+                capacity = int(parts[4].rstrip("%"))
+                filesystems.append({
+                    "filesystem": parts[0],
+                    "mountpoint": parts[5],
+                    "total": total,
+                    "used": used,
+                    "available": available,
+                    "capacity": capacity,
+                })
+            except (ValueError, IndexError):
+                continue
+
+        return {"filesystems": filesystems}
+    except Exception as e:
+        logger.error(f"Error getting disk usage: {e}")
+        return {"error": str(e)}
+
+
 def get_journal_logs(limit: int = 20) -> Dict[str, Any]:
     try:
         result = subprocess.run(
diff --git a/frontend/app/page.tsx b/frontend/app/page.tsx
index 9146f9f..081e705 100644
--- a/frontend/app/page.tsx
+++ b/frontend/app/page.tsx
@@ -24,6 +24,7 @@ export default function Dashboard() {
   const [networkInfo, setNetworkInfo] = useState<any>(null)
   const [networkTraffic, setNetworkTraffic] = useState<any>(null)
   const [diskIO, setDiskIO] = useState<any>(null)
+  const [diskUsage, setDiskUsage] = useState<any>(null)
 
   // History buffers for sparklines (rolling window of 30 points, ~2.5 minutes at 5s intervals)
   const cpuHistoryRef = useRef<number[]>([])
@@ -100,7 +101,7 @@ export default function Dashboard() {
 
   const loadSystemStats = async () => {
     try {
-      const [sysInfo, memInfo, cpuData, uptime, network, traffic, diskio] = await Promise.all([
+      const [sysInfo, memInfo, cpuData, uptime, network, traffic, diskio, diskusage] = await Promise.all([
         api.getSystemInfo().catch(() => null),
         api.getMemory().catch(() => null),
         api.getCpuInfo().catch(() => null),
@@ -108,6 +109,7 @@ export default function Dashboard() {
         api.getNetwork().catch(() => null),
         api.getNetworkTraffic().catch(() => null),
         api.getDiskIO().catch(() => null),
+        api.getDiskUsage().catch(() => null),
       ])
       setSystemInfo(sysInfo)
       setMemoryInfo(memInfo)
@@ -116,6 +118,7 @@ export default function Dashboard() {
       setNetworkInfo(network)
       setNetworkTraffic(traffic)
       setDiskIO(diskio)
+      setDiskUsage(diskusage)
 
       // Add to history
       if (cpuData?.percent !== undefined) {
@@ -524,6 +527,52 @@ export default function Dashboard() {
           </div>
         )}
 
+        {/* Disk Usage (df-based, immer sichtbar wenn Daten vorhanden) */}
+        {diskUsage?.filesystems && diskUsage.filesystems.length > 0 && (
+          <div className="mb-8">
+            <h2 className="text-xl font-semibold mb-4">Disk Usage</h2>
+            <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
+              {diskUsage.filesystems.map((fs: any) => {
+                const pct = fs.capacity
+                const barColor = pct > 85 ? "bg-red-500" : pct > 70 ? "bg-yellow-500" : "bg-blue-500"
+                return (
+                  <Card key={fs.mountpoint}>
+                    <CardHeader className="pb-2">
+                      <CardTitle className="text-sm font-medium text-muted-foreground flex items-center gap-2">
+                        <HardDrive className="w-4 h-4" />
+                        {fs.mountpoint}
+                      </CardTitle>
+                    </CardHeader>
+                    <CardContent className="space-y-3">
+                      <div className="flex items-center gap-2">
+                        <div className="flex-1 h-2 bg-muted rounded-full overflow-hidden">
+                          <div className={`h-full ${barColor} rounded-full`} style={{ width: `${pct}%` }} />
+                        </div>
+                        <span className="text-xs text-muted-foreground w-9 text-right">{pct}%</span>
+                      </div>
+                      <div className="grid grid-cols-3 gap-2 text-sm">
+                        <div>
+                          <p className="text-xs text-muted-foreground">Total</p>
+                          <p className="font-medium">{formatBytes(fs.total)}</p>
+                        </div>
+                        <div>
+                          <p className="text-xs text-muted-foreground">Used</p>
+                          <p className="font-medium">{formatBytes(fs.used)}</p>
+                        </div>
+                        <div>
+                          <p className="text-xs text-muted-foreground">Free</p>
+                          <p className="font-medium">{formatBytes(fs.available)}</p>
+                        </div>
+                      </div>
+                      <p className="text-xs text-muted-foreground truncate">{fs.filesystem}</p>
+                    </CardContent>
+                  </Card>
+                )
+              })}
+            </div>
+          </div>
+        )}
+
         {/* Disk I/O */}
         {diskIO?.disks && diskIO.disks.length > 0 && (
           <div className="mb-8">
diff --git a/frontend/lib/api.ts b/frontend/lib/api.ts
index d101af7..6e259e8 100644
--- a/frontend/lib/api.ts
+++ b/frontend/lib/api.ts
@@ -426,6 +426,11 @@ export class ZFSManagerAPI {
     return response.data
   }
 
+  async getDiskUsage(): Promise<{ filesystems: { filesystem: string; mountpoint: string; total: number; used: number; available: number; capacity: number }[] }> {
+    const response = await this.client.get("/api/system/disk-usage")
+    return response.data
+  }
+
   async getServices(): Promise<{ services: any[] }> {
     const response = await this.client.get("/api/system/services")
     return response.data