8/17/2023 0 Comments Data backup and restore![]() These are included as part of the adapter which is installed on all database VMs by VMware DSM. In this case, the database is backed up using SQL commands such as BACKUP DATABASE and BACKUP LOG, which are run by the sqlcmd utility. This is MS SQL Server for Linux, which is now available as early access in VMware Data Services Manager. Let’s now turn our attention to the third database. We can observe various configuration steps taking place after the OVA has been deployed and before the Database VM is powered on.īacking up and restoring MS SQL Server for Linux In the vSphere client, the following tasks will be observed during a database restore. The original database contents are then restored. The backup script, when executed, calls xtrabackup with the necessary configuration options to complete the backup, which in this case is incremental.Īs mentioned in the PostgreSQL section, a MySQL restore operation similarly involves the deployment of a new Photon OS OVA, the reconfiguration of the VM, the installation and configuration of DSM components, and the creation of a new MySQL database. If a backup is initiated on a standalone MySQL database, the following tasks are observed. Backing up and restoring MySQLįor backing up and restoring MySQL databases, DSM uses Percona’s xtrabackup tool. Highlighted above are the pgbackrest processes used to take the backup of the PostgreSQL database. The pgbackrest processes have been highlighted. Here are some screenshots taken of the running processes before and during a backup of a PostgreSQL database which has been provisioned via VMware DSM. In the event of a crash, the WAL is replayed to make the database consistent. Afterwards, a background process writes the changes into the main database cluster files (also known as the heap). A transaction is considered to be committed when the associated writes are flushed to disk. Transactions are written sequentially to the WAL. WAL is the mechanism that PostgreSQL uses to make sure that no committed changes to the database are lost. Transaction logs in this case refer to the WAL mentioned previously. Then the incremental backups are applied, one by one, to get to the desired/requested PIT.Ī PIT restore (PITR) includes a replay of transactions held in the backed up transaction logs. Thus, when there is a restore, a full back up is first restored. This means that DSM can restore to any PIT (point in time). This mechanism uses the WAL (Write-Ahead Log). VMware Data Services Manager (DSM) has used this mechanism since version 1.4. Backing up and restoring PostgreSQL databasesĭatabase backups and restores are implemented on PostgreSQL using the pgbackrest extension ( ). If recover fails because there is some problem outside of the database data, such as a database VM Guest OS issue, a restore operation would be required rather than a recover operation. Recover is intended to be used as a fast, ‘get out of trouble’ tool. Recover operations are in-place and operates on the same database VM. therefore the restore task requests that you give a new VM name as part of the workflow. As such, a restore is not an in-place restore, but instead creates a whole new database VM. The restore operation involves the deployment of a new Photon OS OVA, the installation and configuration of DSM components, and the creation of a new database before the original database contents are restored. ![]() We do this to avoid propagating any virtual machine issues that might exist in the current database to the restored database database. The most significant difference is that a restore operations recovers the whole of the VM, Guest OS and the database which is running in the VM. Let’s begin with a discussion on the differences between a restore and a recover in VMware DSM. We will look at these operations from the point of view of the different databases which are available in DSM, namely PostgreSQL, MySQL and MS SQL Server for Linux. I also want to highlight the difference between a restore operations and a recover operation since they are significantly different. In this post, I want to look at how VMware Data Services Manager implements backup, restore and recover operations. ![]()
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