Distributed vs Centralized: The Battle of the Databases

Databases are an essential component of any IT strategy. As the primary method of storing and managing your key digital assets, they need to be treated as a mission-critical resource that must be available at all times. With data volumes growing at an exponential rate, and the threats firms face also increasing, it's a good time to look at modernizing your solutions, especially if you haven't reviewed your database strategy in some time.

When developing a modern database solution, there are a few key considerations to take into account. As well as practical matters, such as how data is stored and accessed by users, security is a must-have. This consists of both network security to prevent hackers and physical security. After all, no firewall can defend against someone gaining access to the data center with a portable USB stick.

When you’re building a database, one of the first decisions will be whether to opt for a centralized or distributed solution, as these are the two primary types of database structure. Both have their advantages, so it pays to understand exactly how each works and what the pros and cons are to determine which would be best for you.

What is a centralized database? 

A centralized database is one which is located and stored in a single location in the network. Multiple users are able to access the database and it's easier for them to get a complete view of the data due to its single location. It's also simpler to manage, update and back up information in a centralized database. However, higher usage means that centralized databases can minimize productivity and time efficiency.  

Examples of centralized databases 

Examples of a centralized database are a desktop or server CPU or mainframe computer that users access through a computer network such as a LAN or WAN. 

What is a distributed database? 

A distributed database is one which is split into multiple files found at different locations within the same or an entirely different network. Users can access the nearest database file, which means it offers a faster way of retrieving data. Additionally, users can access and manipulate relevant data to prevent other users from interfering with it. If one database fails, users can still access the system through other files.  

Examples of distributed databases 

Some common examples of distributed databases include: 

• Apache Ignite  
• Apache Cassandra 
• Apache HBase 
• Couchbase Server 
• Amazon SimpleDB 
• Clusterpoint 
• FoundationDB 

The key differences between distributed and centralized options

The principal difference between the two is that, in a centralized database, all your information is stored in a single location. This may be a server within your data center, an individual PC or even a mobile device. Data is then accessed via a network connection (typically a LAN or WAN solution) and is the simplest and most common type of system for most organizations.

In a distributed system, on the other hand, there's no one hub for the information. Instead, data is stored across multiple locations that are all linked together and controlled via a database management system. In this solution, files are spread out over a number of physical locations. This naturally adds cost and complexity for a solution when compared with a centralized database. So why might you consider this as an option?

The advantages and disadvantages of distributed databases 

Here are some of the advantages and disadvantages of a distributed system: 

Advantages 

There are several advantages associated with distributed databases. Firstly, they improve the overall performance of the solution, reducing the time taken for users to access information. This is especially important for large organizations that may require many users to access the database at the same time. 

Speed is another advantage of distributed databases. A centralized system has high usage as multiple users access the database file. In a distributed database, the speed of accessing data is higher as data is retrieved from the nearest file. 

In a centralized system, this places a great deal of load on a single server, but with a distributed alternative, the work is spread over multiple nodes, improving availability and reliability. As different users can access data relevant to them, there's less likelihood of them interfering with each other, while if one database fails, there are other nodes available to take over. 

Disadvantages 

However, aside from the cost and complexity of maintaining a distributed database, it’s also more difficult to obtain a single, complete view of the data as it's spread over multiple physical locations. This may lead to more duplicated and inconsistent data, as well as increased security demands. 

The advantages and disadvantages of centralized databases 

Here are some of the advantages and disadvantages of this type of database: 

Advantages 

By contrast, centralized databases are relatively cheap and easy to manage. Having a single location for storage, location and maintenance allows organizations to access and manage their data more easily, keep visibility and reduce sprawl and duplication. With a single, common source of data, it's easy to get a uniform view of your system. 

From a security perspective, centralized databases also offer a number of advantages. By only needing to manage data in one location, it's easier to restrict both network and physical access to the data, and minimize the risk posed by loss or theft of devices. 

Disadvantages 

However, centralized databases tend to be slower than distributed options. With multiple users needing to access the same files, it can take longer to respond to queries, which harms productivity. What's more, if the database does fail, users will lose access altogether, while critical data can be lost - potentially forever if organizations have failed to put adequate backups in place. 

Which database option is best for you and your team? 

Deciding what's the best option will require balancing the competing needs of cost, convenience, performance and security. A large enterprise may deploy both solutions for differing purposes, depending on the sensitivity and requirements of the data. 

If you have a large team for whom efficiency and fast results are a must-have, a distributed solution may be the only way to go, even if these will come with greater expenses. This prevents bottlenecks and offers the best redundancies. 

Where security is the overriding concern ahead of performance, centralized database solutions will usually win out. This reduces much of the complexity associated with protecting data and keeps risk to a minimum. This may, however, require you to invest in backup and recovery solutions to guard against hardware failures, power outages or other incidents. 

Whichever method you choose, it's important to know what resources you'll require to make it a success. Good planning reduces the risk of any unpleasant surprises further down the line, so knowing the pros and cons is an essential first step.