Beautiful and Painful Redis Cluster Migration

Migrate Keys from One Redis DB to Another Redis DB

#set connection data accordingly
#Will only work for redis > 5.0 
#Easiest way 
#if it doesnt work , then try with  target_db=0 for both
#Also always use  -c  after redis-cli    . Or else the redirection wont work and it will throw (error) Move
#There are multiple ways of doing it. One is  via MIGRATE command  , 2nd is  via DUMP and RESTORE command.


source_host=localhost
source_port=6379
source_db=0
target_host=localhost
target_port=6379
target_db=1


#copy all keys without preserving ttl!
redis-cli -c -h $source_host -p $source_port -n $source_db keys \* | while read key; do echo "Copying $key"; redis-cli -c --raw -h $source_host -p $source_port -n $source_db DUMP "$key" | head -c -1|redis-cli -c -x -h $target_host -p $target_port -n $target_db RESTORE "$key" 0; done