Persistent block storage is a type of storage that retains data even after the associated instance is stopped or restarted. It provides low-latency access and is commonly used for databases, virtual machines, and application storage.
Example: AWS Elastic Block Store (EBS)
Scenario:
Imagine you are running a web application on AWS EC2 that needs to store user data in a MySQL database.
- Create an EC2 Instance:
- You launch an EC2 instance to host your application.
- However, EC2 instances have ephemeral storage, meaning if you stop or terminate the instance, the data is lost.
- Attach an EBS Volume:
- You create an EBS volume (Persistent Block Storage) and attach it to your EC2 instance.
- The EBS volume acts as a hard drive that stores the MySQL database.
- Data Persistence:
- If your EC2 instance stops, the EBS volume retains the data.
- When you start a new EC2 instance, you can reattach the EBS volume and continue using the database without data loss.
- Backup & Snapshot:
- You can take snapshots of the EBS volume for backup and disaster recovery.
Other Examples of Persistent Block Storage
- Google Persistent Disks (for GCP Compute Engine)
- Azure Managed Disks (for Azure Virtual Machines)
- VMware vSAN (for virtualized environments)
