Session 01 - TCO & ROI Analysis

Total Cost of Ownership (TCO) Breakdown

TCO không chỉ là chi phí development. Nhiều technical decisions trở nên tệ vì chỉ tính initial cost mà quên ongoing costs.

5 Components of TCO

Key insight: Development chỉ chiếm 20-30% TCO. Phần lớn chi phí nằm ở maintenance và operations sau khi go-live.

TCO Calculation Template

markdown
## TCO Analysis - [Project/System Name]

### Assumptions
- Team size: [X] engineers
- Fully loaded engineer cost: [$/month]
- Timeline: [X] years
- Expected growth: [X%/year]

### Year 1 Costs
| Category | Item | One-time | Monthly | Annual |
|----------|------|----------|---------|--------|
| **Development** | | | | |
| | Design & Architecture | $X | - | $X |
| | Implementation (X person-months) | $X | - | $X |
| | Testing & QA | $X | - | $X |
| | Migration/Data conversion | $X | - | $X |
| **Infrastructure** | | | | |
| | Compute (VMs/Containers) | - | $X | $X |
| | Database (SQL Server/PostgreSQL) | - | $X | $X |
| | Storage & CDN | - | $X | $X |
| | Networking (bandwidth, VPN) | - | $X | $X |
| **Licensing** | | | | |
| | Software licenses | - | $X | $X |
| | Third-party services/APIs | - | $X | $X |
| **Operations** | | | | |
| | Monitoring & alerting tools | - | $X | $X |
| | On-call rotation (X% of engineer time) | - | $X | $X |
| | Security & compliance | - | $X | $X |
| **Training** | | | | |
| | Team ramp-up | $X | - | $X |
| | Documentation | $X | - | $X |

### 3-Year TCO Projection
| Year | Development | Infrastructure | Operations | Licensing | Total |
|------|------------|---------------|------------|-----------|-------|
| Year 1 | $X | $X | $X | $X | $X |
| Year 2 | $X (maintenance) | $X (+growth) | $X | $X | $X |
| Year 3 | $X (maintenance) | $X (+growth) | $X | $X | $X |
| **Total** | | | | | **$X** |

Ví dụ: On-prem vs Azure Cloud (3 năm)

On-prem nhìn rẻ khi chỉ tính hardware. Tính đủ staff + opportunity cost thì cloud thường thắng.

ROI Calculation

Formula

ROI = (Net Benefit / Total Cost) × 100%

Net Benefit = Total Benefits - Total Costs
Payback Period = Total Investment / Annual Net Benefit

ROI Analysis Template

markdown
## ROI Analysis - [Initiative Name]

### Investment (Costs)
| Item | Amount |
|------|--------|
| Development cost | $X |
| Infrastructure (year 1) | $X |
| Training | $X |
| Migration downtime | $X |
| **Total Investment** | **$X** |

### Expected Benefits (Annual)
| Benefit | How Measured | Annual Value |
|---------|-------------|-------------|
| Reduced development time | Hours saved x rate | $X |
| Fewer production incidents | Incidents x cost per incident | $X |
| Infrastructure cost reduction | Current - new cost | $X |
| Faster time-to-market | Revenue from earlier launch | $X |
| **Total Annual Benefit** | | **$X** |

### ROI Calculation
- Net Benefit (Year 1): $[benefit] - $[cost] = $X
- ROI: ($X / $[investment]) x 100% = X%
- Payback Period: $[investment] / $[annual benefit] = X months

Ví dụ: ROI cho Cloud Migration

Investment:
  Migration development:     $120,000 (3 engineers x 2 months)
  New infrastructure setup:  $10,000
  Training:                  $15,000
  Total:                     $145,000

Annual Benefits:
  Infrastructure savings:    $48,000/year (on-prem $8k/mo → cloud $4k/mo)
  Reduced ops overhead:      $36,000/year (less manual work → 0.5 FTE saved)
  Faster deployments:        $24,000/year (weekly → daily, faster bug fixes)
  Total:                     $108,000/year

ROI = ($108,000 / $145,000) x 100% = 74.5% (Year 1)
Payback Period = $145,000 / $108,000 = 16 months
Year 2+ ROI = much higher (no migration cost, only infra)

Ví dụ: Migrate Monolith sang Microservices

Chi phí migration:
  4 devs x 12 tháng x $8K/tháng = $384K
  Infrastructure mới: $24K/năm
  Training: $10K
  Total: $418K

Lợi ích/năm:
  Giảm deploy time: save 200h/năm x $50/h = $10K
  Giảm downtime: 99.9% → 99.99% = $50K/năm saved
  Scale team độc lập: +30% velocity = $120K value
  Giảm incident response: save $40K/năm
  Total: $220K/năm

Year 1: Negative (investment year)
Year 2: ($440K - $418K) / $418K = 5.3%
Year 3: ($660K - $418K) / $418K = 57.9%
Payback: ~23 tháng

Reality check: Migration ROI thường negative Year 1. Phải trình bày vision 3-5 năm cho management.

Cloud Cost Models Comparison

On-prem vs IaaS vs PaaS vs Serverless

Cost Comparison Example (100K requests/day API)

*On-prem: Khi tính đủ TCO (staff, space, hardware refresh cycle)

Decision Matrix

Choose ON-PREM when:
  ✓ Strict data sovereignty requirements
  ✓ Predictable, constant high load
  ✓ Already own hardware with capacity

Choose IaaS when:
  ✓ Need custom OS configuration
  ✓ Migrating existing apps (lift & shift)
  ✓ Specific hardware requirements (GPU)

Choose PaaS when:
  ✓ Standard web apps and APIs
  ✓ Want managed infrastructure
  ✓ Team focus on code, not ops

Choose Serverless when:
  ✓ Event-driven, sporadic workloads
  ✓ Want zero idle cost
  ✓ Rapid prototyping
  ✗ AVOID for: Long-running processes, consistent high load

Cost Estimation Templates

Engineering Effort Estimation Methods

3-Point Estimate Formula

Expected = (Optimistic + 4 x Most Likely + Pessimistic) / 6
Standard Deviation = (Pessimistic - Optimistic) / 6

Example: Feature X
  Optimistic:  2 weeks
  Most Likely: 4 weeks
  Pessimistic: 10 weeks

  Expected = (2 + 4x4 + 10) / 6 = 4.67 weeks
  SD = (10 - 2) / 6 = 1.33 weeks

  → Communicate: "4-6 weeks, most likely 5 weeks"

Azure Cost Estimation Checklist

• Compute: VM size, App Service plan, Functions
• Database: Instance size, storage, IOPS, read replicas
• Storage: Blob tiers (Hot/Cool/Archive), frequency of access
• Networking: Egress bandwidth, Load Balancer, CDN, VPN
• Data transfer: Cross-region, internet egress (surprise bills!)
• Licensing: SQL Server, Windows (Azure Hybrid Benefit?)
• Support plan: Basic/Developer/Standard/Professional
• Reserved Instances: 1-year vs 3-year discount
• Dev/Test environments: Reduced pricing for non-prod
• Growth factor: Add 20-30% buffer

Presenting Cost Analysis to Management

Presentation Structure

1. Executive Summary (1 slide)
   → "Đầu tư $X, tiết kiệm $Y/năm, ROI X%, hoàn vốn X tháng"

2. Problem Statement (1 slide)
   → Current cost pain point với data

3. Options Comparison (1 slide)
   → Table so sánh 3 options (do nothing, option A, option B)

4. Recommended Option Detail (1-2 slides)
   → TCO breakdown, timeline, risks

5. Ask (1 slide)
   → Budget needed, decision deadline, next steps

Tips trình bày cost cho management

Trade-offs Table

Golden rule: Tối ưu chi phí không phải là cắt giảm - mà là đầu tư đúng chỗ.