Nginx · December 19, 2023

Nginx Tip - Optimize server name hash size with server_names_hash_max_size

Nginx Tip - Optimize server name hash size with server_names_hash_max_size

Nginx is a popular web server software known for its high performance, scalability, and flexibility. It is widely used by many websites and hosting providers, including Server.HK, to deliver content efficiently. One of the key features of Nginx is its ability to handle a large number of virtual hosts or server names efficiently using a hash table. In this article, we will explore how to optimize the server name hash size with the server_names_hash_max_size directive.

Understanding the server name hash

When a request is made to an Nginx server, it needs to determine which virtual host or server block should handle the request. Nginx uses a hash table to quickly look up the server name and find the corresponding server block. The server name hash is calculated based on the server name specified in the request.

By default, Nginx allocates a hash table with a size of 512 buckets to store the server names. This means that Nginx can handle up to 512 unique server names efficiently. However, if you have a large number of server names, you may encounter hash collisions, which can degrade performance.

Optimizing the server name hash size

To optimize the server name hash size, you can increase the value of the server_names_hash_max_size directive in the Nginx configuration file. This directive specifies the maximum size of the hash table in buckets. By increasing this value, you can accommodate more server names and reduce the likelihood of hash collisions.

For example, if you have 1000 unique server names, you can set the server_names_hash_max_size directive to a value greater than 1000. It is recommended to set the value to the nearest power of 2 that is greater than the number of server names. In this case, you can set it to 1024.

To configure the server_names_hash_max_size directive, open the Nginx configuration file (usually located at /etc/nginx/nginx.conf) and add or modify the following line:

http {
    server_names_hash_max_size 1024;
    ...
}

After making the changes, save the configuration file and restart Nginx for the changes to take effect.

Benefits of optimizing the server name hash size

By optimizing the server name hash size, you can improve the performance and scalability of your Nginx server. Here are some benefits:

  • Reduced hash collisions: By increasing the hash table size, you can reduce the likelihood of hash collisions, which can improve the lookup speed and overall performance of your server.
  • Ability to handle more server names: With a larger hash table, you can accommodate a larger number of server names without sacrificing performance.
  • Improved scalability: Optimizing the server name hash size allows your Nginx server to handle more virtual hosts, making it more scalable for growing websites or hosting environments.

Overall, optimizing the server name hash size is a simple yet effective way to enhance the performance and scalability of your Nginx server.

Summary

In conclusion, optimizing the server name hash size with the server_names_hash_max_size directive can significantly improve the performance and scalability of your Nginx server. By increasing the hash table size, you can reduce hash collisions and handle a larger number of server names efficiently. If you are looking for reliable and high-performance VPS hosting solutions, consider Server.HK. Our Hong Kong VPS Hosting plans are designed to meet the needs of businesses and individuals who require fast and secure hosting services.

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