How does WordPress use Redis to accelerate the cache plugin? CWP enables Redis cache

You may have heard of APC/APCu, Opcache, Xcache, they can speed up significantly WordPress or any kind of supported php script.

In this tutorial, I'll show you how to speed up WordPress with Redis Object Cache, and we'll go ahead and install Redis Cache on CWP, so let's get started.

What is a Redis cache?

• Redis is the abbreviation of RE mote DI actionary Server.
• Redis is a fast, open source in-memory key-value data structure store.
• Redis comes with a common set of in-memory data structures that allow you to easily create a variety of custom applications.
• Primary use cases for Redis include caching, session management, pub/sub, and leaderboards.
• Redis is the most popular key-value store today.
• Redis is BSD licensed, written in optimized C code, and supports multiple development languages.

How to enable Redis cache database in CWP control panel?

step 1:Go to CWP Control Panel

• Select "PHP Settings" and then "PHP Version Switcher";
• Then select "PHP Version" from the drop-down list, it is recommended to install the latest version of php 7 ▼
• After the page reloads, you will see the PHP option available for installation (checkbox)

Navigate to the bottom and find " redis " and select it and click " Build ” button, after the php rebuild process is complete, you can check if redis is running with the following command▼

service redis status

You will get output like this (inCentOS Tested on 7, CentOS 6 has different output like "running")

[root@demo ~]# service redis status
Redirecting to /bin/systemctl status redis.service
● redis.service - Redis persistent key-value database
Loaded: loaded (/usr/lib/systemd/system/redis.service; enabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/redis.service.d
└─limit.conf
Active: active (running) since Sun 2022-02-20 16:41:24 +08; 12s ago
Main PID: 2486 (redis-server)
Status: "Ready to accept connections"
CGroup: /system.slice/redis.service
└─2486 /usr/bin/redis-server 127.0.0.1:6379

Everything is fine at this point, now enter the following command to check if php redis is installed▼

php -m | grep -i redis

The output will be like this ▼

[root@demo ~]# php -m | grep -i redis
redis
[root@demo ~]#

If the output is redis , then all is well and we'll go ahead and install the WordPress and Redis integration.

How to install CWP7 control panel, please see here ▼

How to install CWP Control Panel? CENTOS WEB PANEL Configuration Tutorial

How to install CWP Control Panel? CENTOS WEB PANEL configuration tutorial Network promoters use VPS to build a website, there are many free or paid control panels to choose from.When you don't know how to choose a full-featured VPS control panel, the CWP control panel is recommended.Varied……

How to Enable Redis Cache Acceleration Plugin in WordPress?

step 2:Before enabling the redis-object-cache plugin in WordPress, you must wp-config.php Add the following definitions to the file ▼

define( 'WP_CACHE_KEY_SALT', 'www.chenweiliang.com:' );

• will www.chenweiliang.com Replace with your website.

If I have multiple Redis on one server, how do I configure them so that data is not mixed up?

There are two ways.

The first method is to configure different Redis DBs for different sites.

Just add the following configuration to your wp-config.php file so that different sites can use different Redis databases.

You can set different Redis databases incrementally starting from 0.

define( 'WP_REDIS_DATABASE', 0 );

The second way is that Redis cannot be controlled and the same database must be used.

Then you can add different salts in it, so that even if you use the same database, the data will not be confused ▼

define( 'WP_CACHE_KEY_SALT', 'www.chenweiliang.com:' );

step 3:login to WordPress backend → Go to "Plugins" → "Install Plugins" ▼

• you need to add thisWordPress plugin : Redis Object cache

step 4:assuming you have installed Redis Object cache plugin, now navigate to Redis settings and click "Enable Object Cache".

After WordPress enables the Redis Cache Acceleration plugin, it will display "Connected" as shown below▼

• congratulations!WordPress Redis Cache Acceleration Plugin successfully enabled!
• You will notice that the load is now reduced and the site loads very fast.

Special statement: If the program installed by default is in English, the screenshot is taken for grantedis in English.

• However, some Chinese people say "the Chinese website uses English screenshots", "the arrows of the pictures are different"...
• It can be seen that these Chinese people are completely restricted from free thinking.
• Maybe because China is not an open and free country. If so, it seems that there is no freedom to speak and learn English in China at all?

How to configure the Redis cache acceleration plugin?

In general, it is enough to start directly, or we can further configure.

Add the following configuration to our wp-config.php file▼

define('WP_REDIS_CLIENT', 'pecl'); // 指定用于与 Redis 通信的客户端, pecl 即 The PHP Extension Community Library
define('WP_REDIS_SCHEME', 'tcp'); // 指定用于与 Redis 实例进行通信的协议
define('WP_REDIS_HOST', '127.0.0.1'); // Redis 服务器的 IP 或主机名
define('WP_REDIS_PORT', '6379'); // Redis 端口
define('WP_REDIS_DATABASE', '0'); // 接受用于使用该 SELECT 命令自动选择逻辑数据库的数值
define('WP_CACHE_KEY_SALT', 'www.chenweiliang.com:'); // 设置所有缓存键的前缀（ WordPress 多站点模式下使用）
define('WP_REDIS_MAXTTL', '86400');

How to check whether Redis cache is in effect?

Use the following command to check whether the local Redis cache is generated ▼

redis-cli monitor

• Enter your website, refresh the page, and you can see that there is data output.

Redis caching may also cause WordPress plugins and WordPress theme modifications to not take effect.

Command to delete Redis cache manually▼

redis-cli flushall

#进入redis
redis-cli

#清空
flushall

#退出
exit

View the memory configuration of Redis ▼

redis-cli info memory

Back to query results ▼

# Memory
used_memory:24645472
used_memory_human:23.50M
used_memory_rss:40558592
used_memory_rss_human:38.68M
used_memory_peak:140777552
used_memory_peak_human:134.26M
used_memory_peak_perc:17.51%
used_memory_overhead:1619888
used_memory_startup:811872
used_memory_dataset:23025584
used_memory_dataset_perc:96.61%
allocator_allocated:24964648
allocator_active:26865664
allocator_resident:37646336
total_system_memory:17179869184
total_system_memory_human:16.00G
used_memory_lua:37888
used_memory_lua_human:37.00K
used_memory_scripts:0
used_memory_scripts_human:0B
number_of_cached_scripts:0
maxmemory:0
maxmemory_human:0B
maxmemory_policy:noeviction
allocator_frag_ratio:1.08
allocator_frag_bytes:1901016
allocator_rss_ratio:1.40
allocator_rss_bytes:10780672
rss_overhead_ratio:1.08
rss_overhead_bytes:2912256
mem_fragmentation_ratio:1.65
mem_fragmentation_bytes:15954144
mem_not_counted_for_evict:0
mem_replication_backlog:0
mem_clients_slaves:0
mem_clients_normal:20496
mem_aof_buffer:0
mem_allocator:jemalloc-5.1.0
active_defrag_running:0
lazyfree_pending_objects:0
lazyfreed_objects:0

The following is how to configure the pid file after starting the Redis cache▼

Redis can't find pid? How to configure the pid file location address after Redis starts

Redis startup can't find pid file location? Where is the pid file for Redis? How does Linux view the location address of the Redis process pid file? Linux find redis process command ▼ps -ef | grep redis returns the following query results ▼redis 28221...

Solve the problem that the Redis server fails to start

After restarting the VPS server, the Redis server may fail to obtain remote connection access.

Troubleshoot Redis server startup failure: solve the problem of restarting and unable to obtain remote connection access

To run the latest version of Redis with systemd, you need to edit the Redis configuration file:

/etc/redis.conf

Build and configure Redis with systemd support ▼

daemonize no

supervised auto

• Try to restart the VPS server. If Redis can start as usual, it means that the Redis configuration file just edited works.