This guide walks you through configuring Redis cache for a Joomla site hosted on SPanel. By the end, Redis will be deployed on your account, connected inside Joomla’s Global Configuration, and confirmed to be handling live cache traffic. You’ll need SPanel access, administrator access to your Joomla site, and the PHP Redis extension enabled for your site’s PHP version.
One thing to note – Redis only speeds up Joomla once Joomla is configured to use it. Deploying Redis on its own changes nothing until the connection is made and verified, which is why the verification step matters as much as the setup.
Redis is one of several performance and management tools included at no extra cost on every ScalaHosting managed VPS, alongside the rest of SPanel. Deploy Redis, connect Joomla, confirm it in the monitor, and you’ll have a faster site with the controls to keep it that way.
Redis is an in-memory data store. Joomla can use it as a cache, which means that instead of rebuilding the same data on every request, Joomla keeps frequently reused results in memory and serves them from there. The database does less repetitive work, and pages that lean on that data come back faster.
It helps to be clear about what Redis will not do, because setting expectations up front saves troubleshooting later:
Confirm each of these before you start:
SPanel provisions a separate Redis instance for your hosting account on demand. Deploying it takes one click and gives you the two values Joomla needs: a host and a password.
Note: SPanel provisions one Redis instance per hosting account, not one per site. If you run several sites under the same account, they will share this Redis. Part 2 and Part 5 explain how to keep them separated and what that means when you flush.
With Redis deployed, point Joomla at it from the administrator dashboard. The connection fields live in Joomla’s Global Configuration.
Note: Running more than one site under the same account? Give each site a different Redis Database number (0, 1, 2, and so on) in its Joomla configuration. All sites still use the same Redis instance, but numbered databases keep their keys from colliding.
Do not assume the connection worked because Joomla saved without an error. Confirm it. This is where SPanel’s built-in monitor and stats earn their place, because they show you the actual traffic reaching Redis rather than leaving you to guess.
Tip: The monitor is a debugging tool. It displays the real keys and commands your site sends, which is exactly what you want when confirming a setup or chasing a caching bug, so treat its output as sensitive and run it only as long as you need.
A fresh deploy gives you a 256 MB memory budget and the allkeys-lfu eviction policy. Both are set on the SPanel Redis Cache screen and both are adjustable.
There is no single correct number, and Joomla-specific sizing depends on your extensions, traffic, and what you cache. Rather than borrow figures from a different platform, use what your own instance tells you:
Rule of thumb: Start with the SPanel default, observe Redis memory and eviction statistics, and adjust based on actual usage.
If the stats show Redis sitting well under its budget, you have headroom to spare. If it is constantly full and evicting keys to make room, that is the signal to raise the memory limit or reconsider what you are caching.
Eviction policies are simply the rules Redis follows when memory fills up and needs room for new keys. The default, allkeys-lfu, discards the least-frequently-used keys first, which protects the data your site reaches for most. SPanel exposes the full set of eight Redis policies in a dropdown, so you can match the policy to your workload. For a standard Joomla cache, the default is the right starting point, and there is no need to change it unless your usage gives you a specific reason to.
When you deploy new code, change a template, or update an extension, Redis can keep serving the old cached data. The fix is a flush, and SPanel puts that button in your hands rather than behind a support ticket.
On the Redis Cache screen, click Flush Cache. It wipes every key, and Joomla rebuilds the cache as visitors browse. Joomla’s own Clear Cache tool under System does a similar job from the application side; flushing at the SPanel level clears the instance itself.
Warning: Flush removes every key in your account’s Redis instance. Because one Redis serves the whole account, flushing affects all sites that share it, not just the one you have in mind. There is no partial flush.
Most Redis-and-Joomla issues come down to a handful of causes. Work down this table from the symptom you are seeing.
| Problem | Likely reason | What to check |
| Redis deployed, but the monitor shows no commands from Joomla | Joomla is not actually using Redis | Cache Handler is set to Redis, System Cache is ON, and you clicked Save & Close |
| Authentication error or connection refused | Wrong password, host, or port | Re-copy the host and password from the Redis Cache screen and confirm the port matches |
| Site errors right after enabling Redis | The PHP Redis extension is missing | Enable the Redis extension for the site’s PHP version in PHP Manager, then retry |
| Redis shows as stopped | The service was stopped or crashed | Start or Restart it from the Redis Cache screen; SPanel also auto-restarts on failure |
| Keys constantly evicted or memory always full | Cache is larger than the memory budget | Review stats, then raise the memory limit or reduce what you cache |
| Stale content after an update | Old keys are still cached | Use Flush Cache, then reload the affected pages |
| Two sites showing each other’s cached data | Sites share one account Redis on the same database number | Give each site a different Redis Database number in its Joomla configuration |
On an unmanaged server, configuring Redis means installing the daemon, creating its service, assigning a private address, generating a password, configuring auto-restart, and building your own way to watch it. That is a real amount of setup before you cache a single key.
SPanel does that infrastructure work for you. Deploying Redis provisions the instance, its private loopback address, its unique password, and its service, with auto-restart on failure already configured. From then on, the lifecycle controls, configuration, stats, monitor, and flush are all buttons on one screen.
Note: SPanel manages the Redis infrastructure, not your Joomla settings. It does not configure Joomla for you, so Part 2 is still a step you complete yourself.
A few boundaries are worth knowing so the setup matches what Redis on SPanel actually offers:
Q: Do I need to be a developer to set up Redis for Joomla?
A: No. Joomla has a built-in Redis cache handler, so the setup is a matter of deploying Redis in SPanel and entering the host and password in Joomla’s Global Configuration. No code changes are required.
Q: Does Redis replace my Joomla database?
A: No. MariaDB stays the source of truth. Redis holds fast copies of frequently used data so the database does less repeat work, but the database still stores everything permanently.
Q: How much memory should I give Redis for Joomla?
A: Start with the SPanel default of 256 MB, watch the Redis memory and eviction stats, and adjust from there. Raise the limit if the instance is constantly full and evicting keys.
Q: Can I run Redis for more than one Joomla site on the same account?
A: Yes. The sites share one Redis instance, so give each one a different Redis Database number in its Joomla configuration to keep their keys separate.
Q: How do I clear Joomla’s Redis cache after an update?
A: Click Flush Cache on the SPanel Redis Cache screen to wipe the instance, or use Joomla’s own Clear Cache tool under System. Remember that a SPanel flush clears every site sharing that Redis.
