박문형 2015-12

메인서버가 뻗으면 백업서버가 돌아가나요??

강제적으로 메인서버를 죽이고 백업서버를 돌렸을때 잘 돌아간다면 문제 없지만

백업서버가 재대로 안돌아간다면 백업을 한 의미는 화일카피밖에 안될 것입니다.

오프라인 2015-12

Making Backups by Copying Table Files

For storage engines that represent each table using its own files, tables can be backed up by copying those files.
For example, MyISAM tables are stored as files, so it is easy to do a backup by copying files (*.frm, *.MYD, and *.MYI files).
To get a consistent backup, stop the server or lock and flush the relevant tables:

FLUSH TABLES tbl_list WITH READ LOCK;

You need only a read lock; this enables other clients to continue to query the tables while you are making a copy of the files
in the database directory. The flush is needed to ensure that the all active index pages are written to disk before you start the backup.
See Section 13.3.5, “LOCK TABLES and UNLOCK TABLES Syntax”, and Section 13.7.6.3, “FLUSH Syntax”.

You can also create a binary backup simply by copying all table files, as long as the server isn't updating anything.
(But note that table file copying methods do not work if your database contains InnoDB tables.
Also, even if the server is not actively updating data, InnoDB may still have modified data cached in memory and not flushed to disk.)

요약해보면 DB파일을 복사하려면 서버가 업데이트되지 않아야 하고, InnoDB는 그러한 경우에도 flush가 안되서 동작을 하지 않는다... 죠

회원K 2015-12

안됩니다. 그렇게 하려면 rsync를 하면 안되고 percona 와 같은 툴을 써야 합니다.

그래나다 2015-12

아.... InnoDB쓰는데 레플리케이션도 심각하게 고려를 해 보아야 할 거 같습니다....