When it comes to server-side caching solutions, there are no bigger names than Memcached and Redis. These caching solutions dominate the industry and are used by some of the largest websites.
Each has distinct advantages and disadvantages. So, which one you choose depends on your website needs. Of course, this applies to almost everything when it comes to web design.
It’s all about what works best for your particular situation.
However, when I run a generic website, I get similar results to each other. The real difference comes in large websites with much more data than typical blog sites.
Let’s take a look at what these solutions are and how they compare to decide which one is right for you.
Memcached and Redis: An Overview
Before we dive into the details of each caching solution, let’s take a quick look at each one. See other sections listed below for more information.
What is Memcached?
Memcached is a free and open source caching solution invented in 2003. Store data using strings. The amount of data that can be stored is only limited by the hardware on which it is stored.
Therefore, it can be easily expanded by adding more hardware.
When it runs out of space to store data, it starts overwriting the oldest data that hasn’t been used in a while. This can be a bit of an issue in some industries, so proper steps should be taken to ensure no important information is lost.
What is Redis?
Redis, or Lesmote dicivil servant S.erver is an open source caching solution that prioritizes performance over other solutions. Invented in 2009.
It uses several types of data (strings, hashes, lists, sets, sorted sets) to store data and provide quick access to the stored data. You can also edit the above data without loading it, which speeds up the solution.
If the memory limit is reached, Redis will return an error instead of deleting old data. Overall, users can enjoy a fast caching experience on her website.
Memcached vs. Redis: Data Storage
Both Memcached and Redis are great at storing data, but they do it in very different ways. This gives each one an advantage over the other in certain situations.
Let’s see how each one works.
Memcached: data storage
Memcached stores all data as string keys and up to 250B keys and up to 1MB values. The stored data takes up very little space compared to other server-side caching solutions, making it attractive for large websites.
I am using slabs. This splits the memory into multiple chunks of varying sizes. The key is then stored in chunks corresponding to its size to avoid memory fragmentation.
As for storage capacity, it is limited by the amount of memory available on your hardware. It can grow as needed, making it very scalable for large websites.
Memcached is used by the world’s largest websites like YouTube.
Redis: data storage
Redis stores data using five unique data types, including:
- sorted set
Data types offer an advantage over other caching solutions that allow access to individual fields within a single field. This allows the system to perform CRUD (Create, Read, Update, Delete) functions as needed.
Redis supports keys with values up to 512MB. It also supports data type manipulation, so you can edit stored data without loading it.
This not only avoids loading the data, but also saves time by not having to save the data again.
Redis utilizes a master/slave architecture that helps add redundancy to your system. If the master fails, the slave is promoted to take its place.
This makes it harder to maintain Redis on large sites due to its complex architecture, but it makes it more secure.
Memcached and Redis: Setup
Many users are building websites for the first time and are looking for the easiest caching solution to manage.
Let’s take a quick look at each.
One of the main reasons Memcached is a dominant force in the industry is its simplicity. Getting started with Memcached on your Windows or Unix device is very easy. It can also be adapted to any language such as PHP, C, etc.
Depending on how dominant it has been over the years, there are different resources available to help you out.
Web hosts often set this on request. Also, in some cases, some platforms have additional tools that make setup and management easier.
Setting up Redis is a bit complicated, but not difficult for a standard site. More and more web hosts support Redis and help install it on their web servers on demand. That said, they won’t help you manage it.
Resources are becoming more readily available, but generally less.
That said, tools are emerging to make setup easier. For example, WordPress can set up Redis in just a few minutes with the Redis Object Cache plugin.
It’s worth pointing out that in more complex networks Redis is much more flexible with regards to setup. This can lead to more complexity, especially if you need to run multiple nodes simultaneously.
Memcached vs Redis: Persistence
Some websites require persistence from caching solutions. This means that saved data will not be lost if the web server is restarted for any reason. Only one of these solutions supports this feature.
Memcached does not support persistence operations. The data will be lost when the server is restarted.
Is Redis persistent?
Yes, Redis offers several options when it comes to persistence. These include:
- RDBs (Redis database)
- AOF (append-only file)
- No persistence
- RDB + AOF
of Redis official documentation I will elaborate on the robust options available. To keep it simple, you can always restore your data quickly. This will get your website up and running in seconds.
Memcached vs. Redis: WordPress Sites
Chances are your website is built using WordPress and both of these caching solutions work. But these solutions are no longer equivalent and one is beginning to outperform the other.
However, your results will vary depending on the type of website you’re building.
Memcached: WordPress Sites
Memcached has long been the go-to caching solution for WordPress. It is very easy for users to set up and performs great right out of the box.
As such, there are various caching plugins that can take advantage of Memcached, such as W3 Total Cache.
Memcached is a good caching solution when your website always serves the same page to your visitors. This is especially true for one-page business sites because of their fast response times. This significantly reduces page load times.
In many cases, this is still the default caching solution for many web hosts.
Redis: WordPress site
Redis has gained momentum over the last few years and has become the best caching solution for most WordPress sites.
Stores data in memory using server RAM. It stores less data but is much faster than other solutions.
Most of the time, your average WordPress blog will never exceed what your web server’s RAM can handle. This makes it the fastest solution available, but it’s not as easy to set up as other solutions.
The good news is that due to its explosive popularity, most web hosts have started supporting Redis and can help you with the installation process.
Redis is a great option for a standard WordPress site if your website cares about speed.
Memcached vs. Redis: Which Is Better?
A lot depends on what kind of site you’re running, but on a general level, especially in the WordPress ecosystem, Redis is a better option.
Getting it right will give you the fastest caching experience and more features available.
This gives you a lot more flexibility when working with larger datasets. Of course, with this flexibility comes complexity. Compared to Memcached, Redis is a little more difficult to maintain and manage, but the performance gains are worth the effort.
However, both solutions work for most websites. It just depends on the data you’re working with and your ability to properly configure each one for your situation.
Which caching solution did you choose? Did you notice any performance improvements when switching from one solution to another?