03: OCI ‐ Tenancy ‐ Region ‐ AD ‐ FD - pavankumarchittajallu/OCI_DOC GitHub Wiki

1. Tenancy

  • A tenancy in the Oracle Cloud account acts as a secure, isolated container where you create and manage all your cloud resources (e.g., compute instances, storage, networks).
  • It is the organization’s "home" in Oracle Cloud.
  • Created automatically when you sign up for Oracle Cloud Infrastructure (OCI).

Key Features:

  1. Root compartment for organizing resources.
  2. Tied to a single subscription (usually one per organization).
  3. Use compartments to group resources (e.g., by team, project).

2. Region

  • A region is a geographic area where Oracle hosts its cloud infrastructure (e.g., Mumbai, London, Tokyo).
  • Regions are independent of each other and separated by large distances.

Purpose:

  1. Data residency (compliance with local laws).
  2. Disaster recovery (host resources in multiple regions).

Example: If you deploy resources in the Mumbai region, they are physically stored in Oracle’s data centers in India.

3. Availability Domain (AD)

  • An availability domain (AD) is one or more data centers within a region.
  • Each region has 3 ADs for redundancy.
  • ADs are isolated but connected via low-latency networks.

Purpose: High availability: Deploy resources across ADs to survive data center failures.

Example: Hosting a database in AD1 and a backup in AD2 within the same region.

4. Fault Domain (FD)

  • A fault domain (FD) is a logical group of hardware (servers, storage) within an AD.
  • Each AD has 3 FDs.
  • FDs protect against hardware failures (e.g., power supply, rack issues).

Purpose: Distribute resources across FDs to avoid single points of failure.

Example: Placing two VM instances in FD1 and FD2 ensures one survives a hardware crash.

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