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This article mainly introduces how to use the innobackupex command backup, the article is very detailed, has a certain reference value, interested friends must read it!

At the beginning of the backup, a background detection process is started to detect changes in the mysql redo log (transaction log) in real time. Once a new log is found in the redo log, it is immediately recorded in the background log file xtrabackup_log file, and then the Innodb data file and the system tablespace file ibdata1 are copied. After the copy is finished, perform the flush tables with read lock operation, copy .frm, .MYI Files such as .MYD (the purpose of executing flush tables with read lock is to prevent DDL operation when reading data, and to get the location of binlog at this moment), finally issue unlock tables, set the table to read and write state, and finally terminate the writing of xtrabackup_log file. The process is shown in the following figure:

Complete recovery: the recovery phase starts the innodb instance embedded in xtrabackup, plays back the transactions in the xtrabackup log xtrabackup _ log file, applies committed transaction changes to innodb data files and tablespaces, and rolls back uncommitted transactions, a process similar to failure recovery of innodb instances.

The full recovery process is shown in the following figure:

Incremental backup: incremental processing in the innobackupex incremental backup process, in fact, mainly compared to innodb, for myisam and other storage engines, it is still complete one at a time. The incremental backup process is mainly by copying the pages with changes in innodb. These changed data pages mean that the LSN is greater than the LSN given in xtrabackup_checkpoints. The incremental backup is based on the full backup. The data of the first incremental backup must be based on the last complete backup, and each additional backup is based on the previous backup. The process is the same as complete, except that when the data file is copied, the page that has changed since the last backup since the last backup is greater than xtrabackup_checkpoints. The incremental backup process is shown in the following figure:

Incremental recovery: similar to full recovery, it also requires two steps: the recovery of some data files, where the data files include full backup, incremental backup and playback of committed transactions in xtrabackup_log files, and the second part is the rollback of uncommitted transactions.

The process is shown in figures 1 and 2 below:

The above is all the contents of the article "how to use the innobackupex command to back up". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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