Operating system error number 2 in a file operation.
2019-07-19T08:17:39.332766Z 1 [ERROR] [MY-012593] [InnoDB] The error means the system cannot find the path specified.
2019-07-19T08:17:39.332774Z 1 [ERROR] [MY-012216] [InnoDB] Cannot open datafile for read-only: './dbtest/users.ibd' OS error: 71