🔹 What is Alfresco?

Alfresco (now Alfresco Content Services – ACS) is an open-source Enterprise Content Management (ECM) platform used for:

• Document management
• Records management
• Workflow automation
• Content collaboration

It is Java-based and highly extensible, commonly deployed on Tomcat with a database + content store + search engine (Solr).

🔴 Core Architecture (Deep but Clean)

Alfresco follows a modular, service-oriented architecture with these main tiers:

1. Presentation Layer (UI / Client)

Components:

Share UI (Aikau/Surf, moving to newer UIs)

REST clients (Angular/React apps)

Mobile / external apps

Responsibilities:

User interaction

Document upload/download

Workflow initiation

👉 Communicates via REST APIs (v1 public APIs or internal services)

2. Repository Tier (Core Engine)

This is the heart of Alfresco.

Runs on:

Apache Tomcat (Java Spring-based)

Key Services:

Node Service (content model objects)

Content Service (file handling)

Permission Service (ACL security)

Version Service

Workflow Service (Activiti / APS)

🔹 Data Model (Important)

Alfresco stores everything as a Node in a hierarchy:

Workspace → Store → Node → Properties + Content

Each node has:

Metadata (properties)

Content (binary file)

Associations (relationships)

3. Database Layer (Metadata Storage)

Supported DBs:

PostgreSQL

MySQL

Oracle

Stores:

Node metadata

Permissions (ACL)

Workflow state

Version history

👉 DOES NOT store actual files

4. Content Store (File Storage)

Actual documents are stored in:

File system

NAS / SAN

Cloud storage (S3, Azure Blob)

Structure:

Binary files stored in hashed directory structure

Referenced via DB

5. Search Layer (Solr / Elasticsearch)

Solr is default search engine

Responsibilities:

Full-text indexing

Metadata indexing

Fast search queries

Flow:

Content/Metadata → Indexed in Solr → Queried via API

6. Workflow Engine

Options:

Activiti (embedded)

Alfresco Process Services (APS – BPMN engine)

Used for:

Approval workflows

Business processes

Task management

7. Integration Layer

Supported integrations:

REST APIs

CMIS (Content Management Interoperability Services)

Web Scripts

Java APIs

👉 Enables:

External system integration

Microservices

Custom apps

🔴 End-to-End Flow (Technical)

1. User uploads document via UI

2. Request goes to Repository (Tomcat)

3. Metadata stored in DB

4. File stored in Content Store

5. Solr indexes content + metadata

6. Workflow triggered (optional)

7. Document available for search/retrieval

🔴 Security Architecture

Authentication:

LDAP / Active Directory

SSO (SAML/OAuth)

Authorization:

Role-based access

ACL (Access Control Lists)

Audit:

Activity logs

Version tracking

🔴 Key Alfresco Concepts (Interview Important)

Node (core object)

Store (workspace://SpacesStore)

Aspect (adds behavior to nodes)

Content Model (custom types)

Web Scripts (REST endpoints)

Solr Index

🔴 Performance & Scaling

Horizontal Scaling:

Multiple Tomcat instances

Load balancer

Bottlenecks:

Solr indexing delays

DB queries

Content store I/O

Optimization:

DB tuning

Solr sharding

Caching

🔴 High Availability Design

DB clustering

Solr replication

Shared content store

Load-balanced app servers

🔥 Quick Comparison (OnBase vs Alfresco)

Feature OnBase Alfresco

Storage Disk Groups Content Store

DB Metadata only Metadata only

Language .NET / mixed Java

Workflow Built-in Activiti

API Unity / REST REST / CMIS

🔴 When to Use Alfresco

Open-source ECM requirement

Heavy customization

Cloud-native deployments

Microservices integration