What is the role of snapshots in DR?

Snapshots play a critical role in disaster recovery (DR) by providing point-in-time copies of data, systems, or applications. These copies act as restore points, enabling teams to recover quickly from data loss, corruption, or system failures. Unlike traditional backups, snapshots are often stored on the same storage system and can be created frequently with minimal performance impact. For example, a cloud-based virtual machine (VM) snapshot captures the entire state of a VM—including memory, disks, and configuration—at a specific moment. If a disaster occurs, such as a ransomware attack or accidental deletion, developers can roll back to a recent snapshot to restore operations with minimal downtime.

Snapshots work by tracking changes to data blocks over time. When a snapshot is taken, the system records the current state and only saves incremental changes afterward. This approach reduces storage costs and allows for efficient recovery. For instance, a database snapshot might capture all transactions up to a specific timestamp. If the database becomes corrupted, developers can revert to the snapshot to avoid replaying hours of log files. However, snapshots alone aren’t sufficient for full DR strategies. They’re typically stored locally, which means they’re vulnerable to site-wide disasters like hardware failures or natural events. To address this, organizations often replicate snapshots to offsite locations or cloud storage, ensuring redundancy.

A key advantage of snapshots is their speed. Restoring from a snapshot is usually faster than rebuilding from traditional backups because the data is already in a usable state. For example, a developer recovering a compromised Kubernetes cluster could restore a snapshot of its etcd database in minutes rather than reconfiguring the cluster from scratch. However, effective use of snapshots requires planning. Teams must define retention policies (e.g., keeping daily snapshots for a week) and test recovery workflows to avoid surprises during an outage. Combining snapshots with other DR tools—like backups, replication, and failover systems—creates a layered defense against data loss and downtime.