Back up and restore MySQL

Create a logical dump of the InnoDB database:

mysqldump -u root -p \
  --single-transaction \
  --routines --events --triggers \
  notes_app > notes_app.sql

--single-transaction gives a consistent snapshot for transactional InnoDB tables. It does not protect nontransactional tables, and schema changes must not run during the dump. A database dump also does not include MySQL accounts and their grants.

Restore into a clean database, never over the original:

mysql -u root -p -e "CREATE DATABASE notes_restore CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci"
mysql -u root -p notes_restore < notes_app.sql

Verify the restored schema and data:

mysql -u root -p notes_restore -e "SHOW TABLES; SELECT COUNT(*) AS notes FROM notes; CHECK TABLE notes, tags, note_tags;"

Start a non-production application against notes_restore too. A successful dump command alone does not prove recovery works.