There are multiple instances of MySQL Server running on a single OS that is backed up using the mysqldump command. The /etc/my.cnf contains default values, for example, datadir=/var/lib/mysql/, with…

Question

Options

• A--restore=2
• B--copy-back-from-log
• C--backup-instance=/var/lib/mysql/instance2
• D--instance=/var/lib/mysql/instance2
• E--defaults-file=/etc/mysql/instance2.cnf

• A
  2% (1)
• B
  6% (3)
• C
  2% (1)
• D
  13% (7)
• E
  77% (41)

Explanation

Option E is correct because mysqlbackup, like all MySQL utilities, reads /etc/my.cnf by default when no config file is specified. Without --defaults-file, the restore command targets the first instance's datadir and settings - not instance2's - causing the data to land in the wrong location or the wrong instance to be configured entirely. Passing --defaults-file=/etc/mysql/instance2.cnf explicitly tells mysqlbackup which instance's configuration (port, socket, datadir, etc.) to use for the operation.

Why the distractors are wrong:

• A (--restore=2) and D (--instance=...) are not valid mysqlbackup options - they are invented distractors with no corresponding functionality.
• B (--copy-back-from-log) is also a fabricated option; the real subcommand for restoring from a backup is copy-back, which is already in the command.
• C (--backup-instance=...) does not exist in mysqlbackup; you cannot point to an instance by data directory path this way.

Memory tip: Any time a MySQL tool behaves unexpectedly in a multi-instance setup, the fix is almost always --defaults-file. Think of it as: "Which instance am I talking to?" - if you don't specify, MySQL tools always assume the default (first) instance.

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