MariaDB 在使用 mariabackup 恢復增量備份後不啟動

作業系統：CentOS 7

MariaDB：mariadb Ver 15.1 Distrib 10.4.12-MariaDB，適用於 Linux (x86_64)，使用 readline 5.1

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我每 7 天在複製從站上創建一次完整備份，並在此基礎上每小時創建一次增量備份。

此腳本用於創建備份：run-mariabackup.sh

要恢復備份，我正在使用此過程。

但是，在恢復備份之後 MariaDB 不會啟動。

systemd: Starting MariaDB 10.4.12 database server...
mysqld: [Note] /usr/sbin/mysqld (mysqld 10.4.12-MariaDB) starting as process 11363 ...
mysqld: [ERROR] mysqld: File '/var/lib/mysql/aria_log_control' not found (Errcode: 13 "Permission denied")
mysqld: [ERROR] mysqld: Got error 'Can't open file' when trying to use aria control file '/var/lib/mysql/aria_log_control'
mysqld: [ERROR] Plugin 'Aria' init function returned error.
mysqld: [ERROR] Plugin 'Aria' registration as a STORAGE ENGINE failed.
mysqld: [Note] InnoDB: Using Linux native AIO
mysqld: [ERROR] InnoDB: Operating system error number 13 in a file operation.
mysqld: [ERROR] InnoDB: The error means mysqld does not have the access rights to the directory.
mysqld: [ERROR] InnoDB: os_file_get_status() failed on './ibdata1'. Can't determine file permissions
mysqld: [ERROR] Plugin 'InnoDB' init function returned error.
mysqld: [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
mysqld: [Note] Plugin 'FEEDBACK' is disabled.
mysqld: [ERROR] Could not open mysql.plugin table. Some plugins may be not loaded
mysqld: [ERROR] Failed to initialize plugins.
mysqld: [ERROR] Aborting
systemd: mariadb.service: main process exited, code=exited, status=1/FAILURE

當然我chown -R mysql:mysql /var/lib/mysql之前已經做過了，所以這個錯誤讓我感到困惑。在此錯誤之後，我嘗試chmod -R 777 /var/lib/mysql查看是否缺少某些權限，但再次啟動 MariaDB 時，我遇到了同樣的錯誤。

以下是我恢復備份的具體步驟：

cd /home/mysqlbackup/
for i in $(find . -name backup.stream.gz | grep '2020-03-12_12-08-44' | xargs dirname); do
       mkdir -p $i/backup;
       zcat $i/backup.stream.gz | mbstream -x -C $i/backup/;
done
mariabackup --prepare --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass
mariabackup --prepare --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass --incremental-dir incr/2020-03-12_12-08-44/2020-03-12_13-24-20/backup/
mariabackup --prepare --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass --incremental-dir incr/2020-03-12_12-08-44/2020-03-12_13-54-25/backup/
mariabackup --prepare --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass --incremental-dir incr/2020-03-12_12-08-44/2020-03-12_14-00-02/backup/
mariabackup --prepare --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass --incremental-dir incr/2020-03-12_12-08-44/2020-03-12_15-00-01/backup/
mariabackup --prepare --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass --incremental-dir incr/2020-03-12_12-08-44/2020-03-12_16-00-01/backup/
systemctl stop mariadb
mv /var/lib/mysql/ /var/lib/mysql_bak/
mariabackup --copy-back --target-dir base/2020-03-12_12-08-44/backup/ --user backup --password mypass --datadir /var/lib/mysql/
chown -R mysql:mysql /var/lib/mysql/
systemctl start mariadb

當權限看起來正確，但您仍然獲得Errcode: 13 "Permission denied"時，接下來要檢查的是安全系統是否導致了問題。在 CentOS 上，該系統是 SELinux。要檢查它是否在強制模式下執行，請執行以下命令：

sestatus

您可以setenforce 0暫時將其更改為許可模式。

為避免該問題：

最初安裝 MariaDB 時，應為所有文件正確設置 SELinux 安全上下文。但是，當您這樣做時mv /var/lib/mysql/ /var/lib/mysql_bak/，您將其刪除。我認為您可以通過簡單地執行restorecon -Rv /var/lib/mysql.

如需參考，請閱讀 MariaDB 知識庫中的此頁面：Security-Enhanced Linux with MariaDB

引用自：https://dba.stackexchange.com/questions/261782