Varnish Cache In Adobe Commerce (Magento 2)

What is Varnish

Varnish Cache is a powerful reverse proxy server that is crucial in optimizing web performance by handling all incoming requests before they reach the web server.

In the context of Caching in Magento 2, Varnish first checks if the requested content is already cached.

Here’s a quick overview of how it works:

Browser → Varnish → Apache/Nginx → PHP-FPM → Magento

When a user requests a page:

• Varnish checks if it already has the page cached.
• If yes → it serves it instantly (a cache HIT).
• If not → it forwards the request to Apache/Nginx, gets the response, stores it, and serves it next time (cache MISS → then HIT).

You can all check the overall process in the video below —

⚙️ Step 1: Install Varnish

Begin by updating your system and installing Varnish:

sudo apt update
sudo apt install varnish -y

Once installed, confirm the version:

varnishd -V

Then, enable and start the service:

sudo systemctl enable varnish
sudo systemctl start varnish

Now Varnish is running and ready for configuration.

🧾 Step 2: Configure Varnish

Open the systemd service file to modify the listening port:

sudo nano /lib/systemd/system/varnish.service

Change:

-a :6081

to:

-a :80

Next, reload the system daemon:

sudo systemctl daemon-reload

🔧 Define Backend Settings

Now, edit the main configuration file:

sudo nano /etc/varnish/default.vcl

Locate the backend default block and update it:

backend default {
    .host = "127.0.0.1";
    .port = "8080";
}

This tells Varnish to forward all uncached requests to Apache, which will now run on port 8080.

🧠 Add Cache Hit/Miss Header

sub vcl_deliver {
    if (obj.hits > 0) {
        set resp.http.X-Cache = "HIT";
    } else {
        set resp.http.X-Cache = "MISS";
    }
}

Finally, restart Varnish:

sudo systemctl restart varnish

🏗️ Step 3: Configure Apache

Next, move Apache to port 8080 so Varnish can handle port 80.

Edit the ports configuration:

sudo nano /etc/apache2/ports.conf

Change:

Listen 80

to:

Listen 8080

Then open your default virtual host file:

sudo nano /etc/apache2/sites-available/000-default.conf

Update:

<VirtualHost *:80>

to:

<VirtualHost *:8080>

Restart Apache to apply the changes:

sudo systemctl restart apache2

At this point, Apache serves backend requests on port 8080, and Varnish handles all frontend traffic on port 80.

🧱 Step 4: Configure Magento’s Default VCL

Magento provides a ready-to-use Varnish configuration file.
First, export it from Magento’s admin panel

then replace the default Varnish configuration:

sudo cp /path/to/magento/varnish.vcl /etc/varnish/default.vcl

(Remember to back up the existing default.vcl before replacing it.)

Restart Varnish once again:

sudo systemctl restart varnish

🚀 Step 5: Verify Everything

Visit your Magento site and inspect response headers.
You should see:

either :

X-Cache: HIT

or :

X-Cache: MISS

A HIT means the response came directly from Varnish’s cache, while a MISS means it was fetched from the backend.

📊 Step 6: Performance Comparison (Apache vs Apache + Varnish)

To validate the performance boost, I used the wrk benchmarking tool under the same test conditions.
The results speak for themselves.

🧮 Apache 2 Only

wrk -t1 -c50 -d10s http://127.0.0.1/Magento248/pub/ --latency
Running 10s test @ http://127.0.0.1/Magento248/pub/
  1 threads and 50 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   852.86ms  525.60ms   1.84s    47.47%
    Req/Sec    34.50     19.16   100.00     69.15%
  Latency Distribution
     50%  822.51ms
     75%    1.36s 
     90%    1.54s 
     99%    1.77s 
  338 requests in 10.02s, 32.71MB read
  Socket errors: connect 0, read 0, write 0, timeout 41
Requests/sec:     33.74
Transfer/sec:      3.27MB

⚡ Apache + Varnish

wrk -t1 -c50 -d10s http://127.0.0.1/Magento248/pub/ --latency
Running 10s test @ http://127.0.0.1/Magento248/pub/
  1 threads and 50 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     3.39ms    1.33ms  29.07ms   75.75%
    Req/Sec    14.75k   228.10    15.00k    91.00%
  Latency Distribution
     50%    3.51ms
     75%    3.99ms
     90%    4.73ms
     99%    7.30ms
  146778 requests in 10.01s, 13.82GB read
Requests/sec:  14669.56
Transfer/sec:      1.38GB

📈 Result Analysis

The difference is remarkable.

Metric	Apache Only	Apache + Varnish	Improvement (Varnish)
Requests/sec	33.74	14669.56	~435× faster
Average Latency	852.86ms	3.39ms	~252× lower latency
P50 Latency (Median)	822.51ms	3.51ms	~234× faster
P75 Latency	1.36s	3.99ms	~341× faster
P90 Latency	1.54s	4.73ms	~326× faster
P99 Latency	1.77s	7.30ms	~243× faster
Total Requests (10 s)	338	146778	~434× more requests handled
Transfer/sec	3.27MB	1.38GB	~422× higher throughput
Timeouts	41	0	No timeouts with Varnish

✅ Conclusion

By setting up Varnish Cache with Apache and Magento 2, you’ve turned your store into a performance powerhouse.

Varnish efficiently handles cached content, while Apache manages dynamic requests in the background.

As shown in the benchmark, Varnish doesn’t just optimize—it revolutionizes response times.
So, if you’re serious about scalability, it’s time to put Varnish in front of your Magento 2 site!

If you require technical support, feel free to email us at [email protected].

Additionally, explore a wide array of solutions to boost your store’s capabilities by visiting the Adobe Commerce modules section.

For expert advice or to create tailored features, hire Adobe Commerce Developers for your project.