You should check your redis.conf file to see the permissions in dir and dbfilename. If the file named in the dbfilename which is located in the path specified in the dir path exists and the permission is also right. then the problem should be fixed.
Hope this will help someone.
P.S.
To find the redis.conf file location, you can use the #ps ax | grep redis to check. Usually it will be passed to the redis-server as input file.
For the dir permissions:it should be 755, for the dbfilename, it should be 644
Sometimes you also need to use top command to check whether the user:group of the redis-server and the owner of dir are consistent. i.e. The redis-server is running by redis:redis, but the dir is under root:root. In this case, you need to chown redis:redis -R dir.
Where exactly is the permission you refer to?
Thanks. In the end I did chmod 666 and then chmod a+x and now it works. I daresay this isn't recommended but I needed to get it working.
dir and dbfilename is owned by redis and 777 but I still get err on save
@chancyWu error details are not shown, and there's no info in log also
@Herokiller then you should check what's wrong with your log first. If no log, it's hard to guess.