Running Apache and MySQL on a VPS with only 1GB of RAM can be challenging. It requires careful optimization. This guide provides practical steps to enhance performance on CentOS/RHEL systems. We will cover Apache and MySQL configurations.

It’s crucial to understand your server’s resource usage. Monitor your memory and CPU usage regularly.

Apache Optimization

Apache is a resource-intensive web server. Optimizing it is crucial for performance. Here’s how:

1. Choose the Right MPM (Multi-Processing Module)

Prefork: Uses multiple processes. Good for compatibility. But it’s memory intensive.

Worker: Uses multiple processes with multiple threads. More efficient than Prefork.

Event: Asynchronous event-driven MPM. Best for high-traffic servers.

For a 1GB RAM VPS, Worker or Event are generally better choices. They consume fewer resources.

2. Adjust `MaxRequestWorkers`

This setting controls the maximum number of simultaneous requests Apache can handle. Setting it too high can lead to memory exhaustion. Setting it too low will cause slow response times.

Calculate an appropriate value based on available RAM and the average memory usage per Apache process. A good starting point is:

MaxRequestWorkers = (Total RAM ─ RAM used by OS and other services) / Average Apache process size

Example: (1024MB ⏤ 200MB) / 30MB = ~27

3. Enable KeepAlive

KeepAlive allows persistent connections. This reduces the overhead of establishing new connections for each request. However, it can also consume more resources if not configured correctly.

Adjust `KeepAliveTimeout` to a reasonable value (e.g., 5-10 seconds). Longer timeouts consume more resources.

4. Disable Unnecessary Modules

Disable any Apache modules that you don’t need. This reduces memory footprint and improves performance. For example:

• `mod_status` (unless you need server status information)
• `mod_info` (unless you need server information)
• `mod_autoindex` (if you don’t need directory listings)

MySQL Optimization

MySQL can also be a resource hog. Here’s how to optimize it:

1. Configure `innodb_buffer_pool_size`

This is the most important setting for InnoDB storage engine. It determines the amount of memory allocated to cache data and indexes. Set it to the largest possible value without starving the OS or other services.

A good starting point is 50-70% of available RAM. For a 1GB VPS, you might use 512-716MB.

2. Adjust `query_cache_size` (MySQL 5.7 and earlier)

The query cache stores the results of SELECT queries. If the same query is executed again, MySQL can retrieve the result from the cache instead of executing the query again. However, the query cache can also be a source of contention.

In MySQL 5.7 and earlier, set this to a reasonable value (e.g., 64MB-128MB). In MySQL 8.0, the query cache is removed, so this setting is not applicable;

3. Optimize Slow Queries

Identify and optimize slow queries. Use MySQL’s slow query log to find queries that take a long time to execute. Use `EXPLAIN` to analyze the query execution plan and identify potential bottlenecks.

4. Tune Other Buffer Sizes

Adjust other buffer sizes, such as `key_buffer_size` (for MyISAM tables) and `tmp_table_size`. These settings depend on your workload.

Operating System Tweaks

Optimize the OS for better performance.

1. Use Swap Sparingly

Swap space allows the OS to use disk space as virtual RAM. However, accessing swap space is much slower than accessing RAM. Avoid excessive swapping.

Adjust the `swappiness` value to control how aggressively the OS uses swap. A lower value (e.g., 10) makes the OS less likely to swap.

2. Disable Unnecessary Services

Disable any services that you don’t need. This frees up memory and CPU resources. Use `systemctl` to manage services.

3. Use a Lightweight Desktop Environment (if applicable)

If you’re using a desktop environment, choose a lightweight one like Xfce or LXDE. These consume fewer resources than heavier environments like GNOME or KDE.