Redis is a high speed caching system for storing objects in RAM. It works well with WordPress and WooCommerce as an object cache for storing transients so they are not stored in the MySQL database. On WooCommerce particularly this can help a lot because of the number of transients used by plugins, orders and shoppers.
Unix sockets operate at a lower level OSI model layer than TCP sockets so they should be faster.
When I ran some basic Redis unix socket benchmarks I found the results quite surprising – unix sockets were 25% faster than TCP sockets for Redis.
These are microsecond benefits, but why not use Redis unix sockets if we can get some extra performance boost?
Configure Redis with Unix Socket
Modify your redis user under which your Redis server daemon should be running.
Test which user Redis is running as with this command
sudo ps aux | grep redis
You should see
redis 78 0.0 0.0 31360 6800 ? Ssl Aug24 61:13 redis-server *:6379
We are going to make the
redis user a member of the
www-data group which Apache, nginx, php5-fpm and php7.0-fpm run as by default on Debian and Ubuntu systems.
sudo usermod -g www-data redis
Create your redis folder that the unix socket will be in.
sudo mkdir -p /var/run/redis/
Set the permissions so the redis user and www-data group own it
sudo chown -R redis:www-data /var/run/redis
Open your Redis configuration
sudo nano /etc/redis/redis.conf
Add the unix socket path and the permissions
775 so the
redis user and
www-data group can execute the redis unix socket.
# create a unix domain socket to listen on unixsocket /var/run/redis/redis.sock # set permissions for the socket unixsocketperm 775 #requirepass passwordtouse bind 127.0.0.1 daemonize yes stop-writes-on-bgsave-error no rdbcompression yes # maximum memory allowed for redis maxmemory 50M # how redis will evice old objects - least recently used maxmemory-policy allkeys-lru
Ctrl+X, Y and Enter to Save and Exit
sudo service redis-server restart
See if the Redis unix socket was created
ls -lh /var/run/redis
And there we go
total 0 srwxr-xr-x 1 redis www-data 0 Sep 10 17:00 redis.sock
Now reconfigure your service to use the Redis socket