You can have 2 strategies:
- Stop MySQL Server and backup (just copy all files to some location) - folder c:/ProgramData/MySQL/data
- Make a full dump of all databases
mysqldump -u root -p --all-databases > c:/backups/all_db.sql
p1 - if You plan rollback exactly for 5.6.30,
p2 - if You plan go till the win, best to have both.
then You must have old installer for revert back at any time, You can download it from official archive - https://downloads.mysql.com/archives/community/
Then You if You decide revert back:
- Uninstall latest MySQL - by windows tools
- Install 5.6.30 from previous step
- Copy folder c:/ProgramData/Mysql/data saved on previous step
- Start MySQL
If You also make a sql dump - You can use normal restore procedure
mysql -u root -p < c:/backups/all_db.sql
, but it work much slower than simple file copy.