Redis¶
Install Redis¶
Redis can be installed from the Remi YUM repository with the following command:
yum install redis --enablerepo=remi
Updating Redis¶
Redis can be updated with the following command:
yum update redis --enablerepo=remi
Version Check¶
You can check the installed version of Redis with the command:
rpm -qa | grep redis
redis-6.2.4-1.el7.remi.x86_64
Install Multiple Instances¶
The following script will install an additional instances of Redis. Simply define the REDISINSTANCE number and the desired REDISPORT in the script. The below example uses:
REDISINSTANCE="3"
REDISPORT="6381"
Redis Creation Script¶
Simply define the REDISINSTANCE number and the desired REDISPORT before running this script:
cat > /tmp/redis-add.sh
Copy and paste this into the terminal, and then press ctrl+d:
#!/bin/bash
########## Running this will check for Base instance, and multi instances.
REDISINSTANCE="3"
REDISPORT="6381"
OS=$(awk -F= '/^NAME/{print $2}' /etc/os-release | awk -F"\"" '{print $2}' | awk -F" " '{print $1}')
REDISVERSION=$(redis-server -v | awk -F" " '{print $3}' | awk -F"=" '{print $2}' | awk -F"." '{print $1}')
if [[ $REDISVERSION = "6" ]]
then
if [[ ! -f /etc/redis/redis.conf ]]
then
echo "File /etc/redis/redis.conf not found, please review"
exit 1
fi
if [[ -f /etc/redis/redis${REDISINSTANCE}.conf ]]
then
echo "File /etc/redis/redis${REDISINSTANCE}.conf already exists, please review"
exit 1
fi
else
if [[ ! -f /etc/redis.conf ]]
then
echo "File /etc/redis.conf not found, please review"
exit 1
fi
if [[ -f /etc/redis${REDISINSTANCE}.conf ]]
then
echo "File /etc/redis${REDISINSTANCE}.conf already exists, please review"
exit 1
fi
fi
if [[ $REDISVERSION = "6" ]]
then
cp -a /etc/redis/redis.conf /etc/redis/redis${REDISINSTANCE}.conf
mkdir /var/lib/redis${REDISINSTANCE}
chown -R redis: /var/lib/redis${REDISINSTANCE}
touch /var/log/redis/redis${REDISINSTANCE}.log
chown redis: /var/log/redis/redis${REDISINSTANCE}.log
sed -i "s/redis.pid/redis${REDISINSTANCE}.pid/g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s/redis.log/redis${REDISINSTANCE}.log/g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s#dir /var/lib/redis#dir /var/lib/redis${REDISINSTANCE}#g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s/port 6379/port ${REDISPORT}/g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s/redis.sock/redis${REDISINSTANCE}.sock/g" /etc/redis/redis${REDISINSTANCE}.conf
fi
if [[ $REDISVERSION != "6" ]]
then
cp -a /etc/redis.conf /etc/redis${REDISINSTANCE}.conf
mkdir /var/lib/redis${REDISINSTANCE}
chown -R redis: /var/lib/redis${REDISINSTANCE}
touch /var/log/redis/redis${REDISINSTANCE}.log
chown redis: /var/log/redis/redis${REDISINSTANCE}.log
sed -i "s/redis.pid/redis${REDISINSTANCE}.pid/g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s/redis.log/redis${REDISINSTANCE}.log/g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s#dir /var/lib/redis#dir /var/lib/redis${REDISINSTANCE}#g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s/port 6379/port ${REDISPORT}/g" /etc/redis/redis${REDISINSTANCE}.conf
sed -i "s/redis.sock/redis${REDISINSTANCE}.sock/g" /etc/redis/redis${REDISINSTANCE}.conf
fi
if [[ $OS = "CentOS" ]]
then
cp -a /usr/lib/systemd/system/redis.service /usr/lib/systemd/system/redis${REDISINSTANCE}.service
sed -i "s/redis.conf/redis${REDISINSTANCE}.conf/g" /usr/lib/systemd/system/redis${REDISINSTANCE}.service
sed -i "s/redis-shutdown/redis${REDISINSTANCE}-shutdown/g" /usr/lib/systemd/system/redis${REDISINSTANCE}.service
cp -a /usr/libexec/redis-shutdown /usr/libexec/redis${REDISINSTANCE}-shutdown
sed -i "s/SERVICE_NAME=redis/SERVICE_NAME=redis${REDISINSTANCE}/" /usr/libexec/redis${REDISINSTANCE}-shutdown
sed -i "s/6379/${REDISPORT}/" /usr/libexec/redis${REDISINSTANCE}-shutdown
systemctl start redis${REDISINSTANCE}.service
systemctl enable redis${REDISINSTANCE}.service
fi
if [[ $OS = "Ubuntu" ]]
then
cp -a /usr/lib/systemd/system/redis-server.service /usr/lib/systemd/system/redis${REDISINSTANCE}.service
sed -i "s/redis.conf/redis${REDISINSTANCE}.conf/g" /usr/lib/systemd/system/redis${REDISINSTANCE}.service
sed -i "s/Alias=redis.service/Alias=redis${REDISINSTANCE}.service/g" /usr/lib/systemd/system/redis${REDISINSTANCE}.service
systemctl enable redis${REDISINSTANCE}.service
systemctl start redis${REDISINSTANCE}.service
fi
Run Redis Creation Script Again¶
Run twice if you want two additional instances (redis2 and redi3)
sh /tmp/redis-add.sh
Check Running Instances¶
ps awux | grep redis
redis 24372 0.2 0.0 153952 2644 ? Ssl 15:37 0:00 /usr/bin/redis-server 127.0.0.1:6381
redis 24645 0.2 0.0 153952 2820 ? Ssl 15:40 0:00 /usr/bin/redis-server 127.0.0.1:6379
Disable Snapshotting¶
Unless you need to preserve session / cache information we recommend you disable Snapshotting to reduce I/O. Comment out everything under SNAPSHOTTING in redis.conf. Typically the following:
#save 900 1
#save 300 10
#save 60 10000
#dbfilename dump.rdb
#dir /var/lib/redis/
Enable asynchronous deletion¶
If you wish to enable asynchronous deletion for performance tuning, you can add the below into your redis.conf:
lazyfree-lazy-eviction yes
lazyfree-lazy-expire yes
lazyfree-lazy-server-del yes
replica-lazy-flush yes
On Redis 6.x or later, you can also add the below:
lazyfree-lazy-user-del yes
Truncate Redis Database¶
Remove or truncate any existing dump.rdb files:
> /var/lib/redis/dump.rdb
> /var/lib/redis/dump2.rdb
> /var/lib/redis/dump3.rdb
OS Settings¶
Redis recommends the following OS settings:
sysctl vm.overcommit_memory=1
sysctl -w net.core.somaxconn=65535
echo never > /sys/kernel/mm/transparent_hugepage/enabled
OS Settings on Startup¶
chmod +x /etc/rc.d/rc.local
echo "vm.overcommit_memory=1" >> /etc/sysctl.conf
echo "net.core.somaxconn=65535" >> /etc/sysctl.conf
echo "echo never > /sys/kernel/mm/transparent_hugepage/enabled" >> /etc/rc.d/rc.local
Redis Status¶
You can run the following command to see the status of a Redis instance. This includes version number, memory usage plus information on the databases:
redis-cli -h 127.0.0.1 -p 6379 info
Flush Single Database¶
To flush a single database. define the database number with -n and run the command flushdb:
redis-cli -h 127.0.0.1 -p 6379 -n 0 flushdb
Flush All Databases¶
redis-cli -h 127.0.0.1 -p 6379 flushall
Monitor Redis¶
You can review the information to and from Redis with the monitor command:
redis-cli -h 127.0.0.1 -p 6379 monitor