Cyber resilience is the ability of an organization to keep operating in the face of cyberattacks and natural disasters. Backups, snapshots, and data replication are very important tools and strategies for cyber resilience, with the same ultimate goal of protecting your data, but they’re often confused.
Let’s explore what each one is, how they differ, some real-world examples, and how Pure Storage provides each of these key elements.
What Is Data Replication?
Data replication means copying data to another location, whether it’s a storage system within the same data center or, more commonly, to a remote data center as a safeguard against data center failure. It’s the process of storing data in more than one site or node so that all users can share the same data without inconsistency.
The result of data replication is a distributed database that enables users to access data relevant to their tasks without interfering with the work of other systems or teams.
Types of Data Replication
There are various types of data replication:
- Synchronous replication replicates all input/output (IO) as it’s written to the data storage system, which commits both local and remote writes before acknowledging to the host that the write is good.
- Asynchronous replication replicates data at specific time intervals—every five minutes, for example—and the changes are then replicated to a remote site. This means that the worst that could happen in this example is that you lose five minutes of data.
- Transactional replication is when users receive full initial copies of the database and then receive updates as data changes.
- Snapshot replication is when data is distributed exactly as it appears at a specific moment in time, thereby creating a “snapshot” of data at that moment that is then sent to users.
- Merge replication is when data from two or more databases is combined into a single database. Merge replication is the most complex type of data replication because it allows both publishers and subscribers to make changes to the database independently.
There’s also full replication, where the entire database is stored at every site, and partial replication, in which only frequently used fragments of a database are replicated.
Pure Storage® ActiveCluster™ maintains data consistency across geographically distributed instances.
When to Use Merge or Transactional Data Replication
Merge replication is typically used in server-to-client environments. It allows changes to be sent from one publisher to multiple subscribers. With transactional replication, data gets copied in real time from the publisher to the receiving database. Transactional replication not only copies the data changes but also replicates each change consistently and accurately. Transactional data replication is typically best for server-to-server environments.
What Is a Backup?
Backup and recovery is the process of creating and storing copies of your data that you can use to restore your organization’s services in the event of a primary data failure due to a power outage, ransomware attack, or other type of disaster.
Backups let you roll back your systems to a previous point in time before the data loss or corruption occurred in order to restore services. You can store backups on the same server as the original data, but it’s generally better to store them on a different server, ideally at a different location, or on a separate system such as a secure cloud server for the sake of creating data redundancy.
What Is RTO vs. RPO?
Recovery time objective (RTO) and recovery point objective (RPO) are key metrics in disaster recovery and business continuity planning. RTO defines how quickly systems and applications must be restored after a disruption to avoid unacceptable downtime, while RPO indicates the maximum acceptable amount of data loss measured in time—essentially how far back in time you can go from the point of failure and still recover usable data. Together, they guide the design of backup, replication, and recovery strategies to meet business requirements for resilience and continuity.
What Is a Snapshot?
A snapshot copies the state of a system at a certain point in time, preserving a virtual picture of your server's file system and settings.
Unlike a backup, which performs a full copy of your data, a snapshot only copies the settings and metadata required to restore your data in the event of a disruption. You still need to store the source files for your snapshots in a separate location to be able to retrieve them.
Data Replication vs. Data Backup
Data replication and data backup are related but not interchangeable.
Data backup involves restoring data to a specific point in time by creating “save points” on your production servers. These save points can later be restored in the event of file corruption, system failure, outages, or any event that causes any type of data loss. Since traditional data backups can take several hours, businesses typically schedule them at night or on weekends.
Although there’s always a risk of losing data between backups, they are still a good standard of data protection and are especially suitable for storing large sets of static data long term. Data backups are a key data protection method for industries that need to keep long-term records for compliance.
Where backups focus on data protection, data replication focuses on business continuity—keeping mission-critical and customer-facing applications running even in the face of a disaster.
