Re: MySQL 5.7 database files

[Barry Galbraith]

An image, and a database backup are two subtley different things.
When MySQL is busy, it can hold data in ram (for faster access) and then write to disk "later".
Your disk image will only capture what's on disk, and miss the data held in ram. Mysqldump can capture all of your database.
And what about database changes since your disk image? Using binary logging, along with mysqldump can do point in time recovery, right up to the last change to your database before the failure.
Image your volume by all means, but if you you want a database backup then you need to backup ALL of your database.

Good luck,
Barry.