Memory management and optimization that you need to pay attention to when building a web server on CentOS

When building a web server, memory management and optimization are very important links. Proper memory management can improve server performance and stability, thereby providing a better user experience. This article will introduce the memory management and optimization methods that need to be paid attention to when building a web server on CentOS system, and provide some code examples.

1. The importance of memory management

Memory is one of the most valuable resources in the server. Proper use of memory can improve system performance. When building a web server, we need to consider the following aspects of memory management:

1. Memory allocation: Allocate memory reasonably according to the actual needs of the server. If you allocate too much memory, it can lead to waste; if you don't allocate enough memory, it can lead to performance degradation or server crashes.
2. Memory release: Timely release memory that is no longer needed so that other applications can use it. Unreasonable memory management may lead to memory leaks and system instability.
3. Cache management: Proper use of cache can reduce the number of reads from the hard disk and improve the system's response speed. However, if the cache is used improperly, it may cause insufficient memory and affect the stability of the system.

2. Memory management and optimization methods

1. Setting virtual memory

Virtual memory is allocated to applications in the server Memory. We can set the size of virtual memory by modifying the system configuration file. Under normal circumstances, it is recommended to set virtual memory to 1.5 times the physical memory.

Open the configuration file /etc/fstab and find the following line:

# /swapfile none swap sw 0 0

Remove the comment symbol # at the beginning of the line and modify it to the following content:

/swapfile none swap sw 0 0

Save and exit the configuration file, execute the following command to make the configuration take effect:

sudo swapon -a

2. Clear the memory cache

The memory cache is a technology used by the operating system to improve performance. However, if there is too much cache, it may cause insufficient memory and affect the stability of the server. We can clear the memory cache through the following command:

sudo sync && echo 3 | sudo tee /proc/sys/vm/drop_caches

3. Optimize database cache

The database is one of the most commonly used applications in web servers. System performance can be improved by optimizing the database cache. We can set the cache size by modifying the database configuration file. Taking MySQL as an example, open the configuration file /etc/my.cnf and find the following line:

#innodb_buffer_pool_size = 128M

Remove the comment symbol # at the beginning of the line and change it to an appropriate value to control the cache size. After saving and exiting the configuration file, execute the following command to make the configuration take effect:

sudo systemctl restart mysqld

4. Optimize PHP cache

PHP is another commonly used application in web servers. By optimizing PHP's cache, you can reduce script compilation time and improve system response speed. We can use PHP's caching tool to manage cache. Taking the APC cache as an example, you first need to install the APC extension:

sudo yum install php-apc

After the installation is complete, open the PHP configuration file /etc/php.ini and find the following line:

;apc.shm_size = 64M

Remove the beginning of the line Comment the symbol ; and change it to an appropriate value to control the size of the cache. After saving and exiting the configuration file, restart the web server for the configuration to take effect.

3. Summary

When building a web server on CentOS, memory management and optimization are crucial. This article introduces some memory management and optimization methods and provides some code examples. Through reasonable memory management and optimization, the performance and stability of the server can be improved, providing users with a better experience. Hope this article is helpful to you.

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