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2Kdyz webova aplikace roste z hlediska uzivatelu, dat a funkci, skalovatelnost se stava prioritou.
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4## Vertikalni vs horizontalni skalovani
5~
6**Vertikalni skalovani (Scale Up):** zvyseni prostredku (CPU, RAM, uloziste) jednoho serveru.
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8**Horizontalni skalovani (Scale Out):** pridani vice serveru/uzlu, ktere pracuji spolecne.
9~
10```mermaid
11flowchart LR
12    A[Users] --> B[Load Balancer]
13    B --> S1[Server 1]
14    B --> S2[Server 2]
15    B --> S3[Server 3]
16```
17~
18## Caching: Zrychleni odpovedi
19~
20```mermaid
21flowchart TD
22    U[User] --> CDN[CDN]
23    CDN --> App[Application]
24    App --> DB[Database]
25```
26~
27## Load Balancing: Rozlozeni provozu
28~
29```mermaid
30flowchart TD
31    U[User] --> LB[Load Balancer]
32    LB --> S1[Server 1]
33    LB --> S2[Server 2]
34    LB --> S3[Server 3]
35```
36~
37## Skalovani databaze: Replikace a Sharding
38~
39```mermaid
40flowchart TD
41    App[Application] --> DB1[Shard 1]
42    App --> DB2[Shard 2]
43    App --> DB3[Shard 3]
44```
45~
46## Mikrosluzby a distribuovane architektury
47~
48```mermaid
49flowchart TD
50    U[User] --> API[API Gateway]
51    API --> MS1[Microservice 1]
52    API --> MS2[Microservice 2]
53    API --> MS3[Microservice 3]
54    MS1 --> DB1[(DB 1)]
55    MS2 --> DB2[(DB 2)]
56    MS3 --> DB3[(DB 3)]
57```
58~
59## Asynchronni zpracovani a fronty uloh
60~
61```mermaid
62flowchart TD
63    App[Application] -- send task --> Queue[Queue]
64    Queue --> Worker[Worker]
65    Worker --> DB[Database]
66```
67~
68## Pokrocile vzory skalovatelnosti
69~
70- **Circuit Breaker:** predchazi kaskadovym selhanim mezi sluzbami.
71- **Bulkhead:** izoluje prostredky mezi komponentami.
72- **Retry and Backoff:** automaticky opakuje neuspesne pozadavky s rostoucimi intervaly.
73- **Rate Limiting:** omezuje pocet prijatych pozadavku.
74~
75```mermaid
76flowchart TD
77    Client --> API[API Gateway]
78    API --> CB[Circuit Breaker]
79    CB --> Svc[Service]
80    Svc --> DB[Database]
81    API --> RL[Rate Limiter]
82    RL --> CB
83```
84~
85## Kompletni technologicky stack
86~
87```mermaid
88flowchart TD
89    CDN[CDN] --> LB[Load Balancer]
90    LB --> API[API Gateway]
91    API --> MS1[Microservice 1]
92    API --> MS2[Microservice 2]
93    MS1 --> Redis[Redis Cache]
94    MS1 --> DB1[(Relational DB)]
95    MS2 --> MQ[Message Queue]
96    MQ --> Worker[Worker]
97    Worker --> DB2[(NoSQL DB)]
98```
99~
100## Kompletni tok pozadavku
101~
102```mermaid
103flowchart LR
104    U[User] --> CDN[CDN]
105    CDN --> LB[Load Balancer]
106    LB --> API[API Gateway]
107    API --> MS[Microservices]
108    MS --> MQ[Message Queue]
109    MS --> Redis[Cache]
110    MS --> DB[Database]
111    MQ --> Worker[Worker]
112    Worker --> DB
113```
114~
115## Zaver
116~
117Skalovani webove aplikace vyzaduje holisticky pohled: architektura, nastroje, automatizace, monitoring a kultura DevOps. Studium pokrocilych vzoru, prijimani osvedcenych postupu a uceni se z chyb velkych firem je klicem k budovani odolnych systemu pripravenych na rust.
118~