Scalability Patterns: Preparing Your Application for Growth

Scaling Isn't Just More Servers

Throwing hardware at a poorly architected application doesn't solve scaling problems—it just makes them more expensive. True scalability comes from architectural decisions that enable horizontal growth.

Stateless Application Servers

// Store session in Redis, not filesystem
SESSION_DRIVER=redis

// Store uploads in S3, not local disk
FILESYSTEM_DISK=s3

// Use database or Redis for cache
CACHE_DRIVER=redis

// Now any server can handle any request

Database Scaling

Read Replicas

// config/database.php
'mysql' => [
    'read' => [
        'host' => [env('DB_READ_HOST_1'), env('DB_READ_HOST_2')],
    ],
    'write' => [
        'host' => env('DB_WRITE_HOST'),
    ],
],

// Laravel automatically routes reads and writes

Query Optimization

// Use chunking for large datasets
User::chunk(1000, function ($users) {
    foreach ($users as $user) {
        $this->processUser($user);
    }
});

// Use cursor for memory efficiency
foreach (User::cursor() as $user) {
    $this->processUser($user);
}

Caching Strategies

// Cache expensive queries
$products = Cache::remember('popular_products', 3600, function () {
    return Product::popular()->with('category')->limit(20)->get();
});

// Cache tags for invalidation
Cache::tags(['products'])->put('product_' . $id, $product);
Cache::tags(['products'])->flush(); // Clear all product cache

Queue Everything

// Don't do slow things in request cycle
class OrderController
{
    public function store(Request $request): Response
    {
        $order = Order::create($request->validated());

        // These happen in background
        SendOrderConfirmation::dispatch($order);
        UpdateInventory::dispatch($order);
        NotifyWarehouse::dispatch($order);

        return response()->json($order);
    }
}

CDN for Static Assets

// config/filesystems.php
'asset_url' => env('ASSET_URL', 'https://cdn.example.com'),

// In views

// Outputs: https://cdn.example.com/images/logo.png

Load Balancing Patterns

• Round Robin: Simple, equal distribution
• Least Connections: Route to least busy server
• IP Hash: Same client always hits same server
• Weighted: More traffic to more powerful servers

Conclusion

Build for horizontal scaling from the start: stateless servers, externalized state, aggressive caching, and background processing. The architecture changes required to scale are much easier to implement early than retrofit later.