Backup Overview

The high level steps involved in performing a full backup of MariaDB ColumnStore are:

• Suspend write activity on the system.
• Backup the MariaDB Server data files.
• Backup the ColumnStore data files.
• Resume write activity on the system.

Backup and Restore for MariaDB CoulmnStore 1.1.0 onwards

In MariaDB ColumnStore 1.1.0 a tool - columnstoreBackup to automate the backup/restore across the MariaDB ColumnStore nodes is available. It is available for download at https://mariadb.com/downloads/mariadb-tx/tools

Note: columnstoreBackup tool is only for ColumnStore data backups. Other engines may not be fully backed up and data could be lost when restoring.

Setup

To run columnstoreBackup you'll need to setup a backup server with passwordless ssh login available for the user account that installed MariaDB ColumnStore. (Default: root) Copy the executable columnstoreBackup onto the backup server. Create a target directory on the backup server to store the files. This directory will need to have enough space to store all ColumnStore data files. Example:

Backup Executable: /home/user/columnstoreBackup
Backup Data Directory: /home/user/columnstoreBackupData/

There is an optional columnstoreBackup.config file that when placed in the same directory as the columnstoreBackup executable will allow you to configure an incremental backup option that uses the rsync link-dest option to enable incremental backups. These are stored in backup.1 thru backup.[n-1] from newest to oldest. The columnstoreBackup.config file should only contain a single line:

NUMBER_BACKUPS=[n]

Where "n" is the number of incremental backups to store. (Default: 3)

Backup/Restore Process for MariaDB ColumnStore 1.0.x

Suspend Write Activity

To suspend data writes to column store the following command can be issued the admin console:

mcsadmin> suspendDatabaseWrites
suspenddatabasewrites   Thu Oct 13 13:18:40 2016

This command suspends the DDL/DML writes to the MariaDB Columnstore Database
           Do you want to proceed: (y or n) [n]: y

Suspend Calpont Database Writes Request successfully completed

Optionally y can be appended as an argument to suspendDatabaseWrites to avoid the confirmation prompt.

Backup the MariaDB Server data files

The MariaDB Server should be backed up using one of the available backup methods described in the server backup and restore overview. Since the column store data is not stored within the MariaDB Server backup should run very quickly. Utilizing either mysqldump or just backing up the directory are straightforward options.

Using mysqldump

For example:

> /usr/local/mariadb/columnstore/mysql/bin/mysqldump --skip-lock-tables --no-data loansdb > mariadb_bkp.sql

Note the --no-data option since only the ddl is required for column store tables. The next step will backup the data files. If tables exist using other storage engines then this is likely not appropriate for these.

Server Data File Directory Backup

Backup can be achieved by simply copying the Server data directories under /usr/local/mariadb/columnstore/.

> cp -rp /usr/local/mariadb/columnstore/mysql/db .

Backup ColumnStore Data Files

Backup can be achieved by simply copying the data directories or using vendor supplied backup or snapshot utilities for those directories. A files and directories in the data<N> directories where N represents a unique directory such as data1, data2, etc for each PM server.

> cp -rp /usr/local/mariadb/columnstore/data? .

Resume Write Activity

To resume data writes to column store the following command can be issued the admin console:

mcsadmin> resumeDatabaseWrites
resumedatabasewrites   Thu Oct 13 13:58:55 2016

This command resumes the DDL/DML writes to the MariaDB Columnstore Database
           Do you want to proceed: (y or n) [n]: y

Resume MariaDB Columnstore Database Writes Request successfully completed

Optionally y can be appended as an argument to resumeDatabaseWrites to avoid the confirmation prompt.

Restore Overview

The high level steps involved in restoring a backup are:

• Restore the MariaDB Instance
• Restore the ColumnStore data files.

Restoring the MariaDB Instance

The appropriate restoration method corresponding to the backup utility used should be performed first to restore the MariaDB server instance.

mysqldump

If mysqldump was utilized then the backup script is run:

> mcsmysql

MariaDB [(none)]> create database loansdb;
Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> use loansdb;
Database changed
MariaDB [loansdb]> source mariadb_bkp.sql
Query OK, 0 rows affected (0.00 sec)
...
MariaDB [loansdb]> exit

Restoring the Server Data Files

Backup can be achieved by simply copying the Server data directories under /usr/local/mariadb/columnstore/.

> rm -rf /usr/local/mariadb/columnstore/mysql/db
> cp -rpf db /usr/local/mariadb/columnstore/mysql

Restoring the ColumnStore Data Files

The data<N> directories should simply be copied from the backup location or restored via an appropriate backup or snapshot utility. For example:

> rm -rf /usr/local/mariadb/columnstore/data?
> cp -rpf data? /usr/local/mariadb/columnstore
> mcsadmin startSystem