تصميم النظام يتعلق بشكل أساسي بـ المقايضات — لا يمكنك تحسين كل شيء في نفس الوقت، لذا التصميم الجيد ينطوي على فهم المقايضات واتخاذ خيارات مدروسة بناءً على المتطلبات والأولويات المحددة. إن التفكير الجيد في المقايضات هو جوهر تصميم النظام.
لا يوجد تصميم مثالي
Every design decision involves TRADE-OFFS → improving one thing often costs another:
→ you CAN'T maximize consistency, availability, performance, cost, simplicity all at once
→ "it depends" → the right choice depends on the specific REQUIREMENTS and priorities
→ system design = making informed trade-offs, NOT finding a universal "best" design.
المقايضات الشائعة
CONSISTENCY ↔ AVAILABILITY (CAP) → strong consistency vs high availability
LATENCY ↔ CONSISTENCY → caching/replication (fast but possibly stale) vs always-current
PERFORMANCE ↔ COST → more resources/caching cost money
SIMPLICITY ↔ SCALABILITY/flexibility → monolith (simple) vs microservices (scalable, complex)
READ ↔ WRITE optimization → denormalization (fast reads, harder writes) vs normalized
SPACE ↔ TIME → precompute/cache (more storage, less compute) vs compute on demand
→ understanding these lets you choose deliberately.
