DB Clustering/ Replication/ Mirroring

• ⭐️ common ground: methods for enhancing DB availability, reliability

✅ DB Clustering

distributed database system across parallel nodes
by grouping interconnected servers to work as a single system

• if one DB has a problem, another DB can continue the work

• 👍🏻 availability ⬆️
• 👍🏻 load balancing ⬆️
• 👍🏻 allow data duplication, data recovery, fault tolerance
• 👍🏻 scalability
• 👎🏻 synchronization among replicated data
• 👎🏻 communication among node complicated

✅ DB Replication

horizontal model
copy several database
multiple copies of data across different devices, systems
several server can access

• 👍🏻 synchronization among replicated data easy
• 👍🏻 data remains up to date
• 👍🏻 data availability, distribution, disaster recovery

• 👎🏻 need to replicate data, more resource use

• snapshot
• transactional replication
• merge replication

✔️ Master-slave replication

• replicate data to slave DB from master DB
• master DB: read & write
• slave DB: read only

✅ DB Mirroring

create exact copy of data from one device to another in real-time

• replicated data 🟰 synchrnoized with origin data

• 👍🏻 redundancy
• 👍🏻 recovery
• 👍🏻 availability ⬆️