Log Shipping Servers

For every PostgreSQL VM whose WAL files you want to back up, Veeam Backup & Replication defines how to ship logs to the backup repository. WAL files can be transported in the following ways:

• Directly from the VM guest OS to the backup repository. This method is recommended — it does not involve additional resources and puts less load on the VM guest OS.
• Via log shipping servers. If it is not possible to establish a direct connection between the VM guest OS and backup repository, you can configure Veeam Backup & Replication to use a log shipping server.

A log shipping server is a Linux server added to the backup infrastructure. You can explicitly define what servers you want to use for log shipping or instruct Veeam Backup & Replication to automatically choose an optimal log shipping server. Depending on the possible data transfer methods and location of the PostgreSQL VM and the log shipping server, Veeam Backup & Replication chooses the log shipping server.

Data Transfer Methods

Log shipping servers can transport data in two ways:

• Over the network. In this scenario, Veeam Backup & Replication obtains files from the VM guest OS and transfers them over the network. This is a default method that uses log shipping servers.
• Over PowerShell Direct. In this scenario, Veeam Backup & Replication obtains WAL files from the VM guest OS over PowerShell Direct, bypassing the network. PowerShell Direct is used for VMs that reside on Microsoft Hyper-V Server 2016 (or later) and run Microsoft Windows 10 (or later) or Microsoft Windows Server 2016 (or later). Veeam Backup & Replication requires Microsoft PowerShell 2.0 (or later) to work over PowerShell Direct.

Location of Log Shipping Server and VMs

When choosing a log shipping server for the job, Veeam Backup & Replication considers the location of the PostgreSQL VM and log shipping server. Veeam Backup & Replication uses the following priority rules to select the log shipping server:

1. The log shipping server is located on the source Microsoft Hyper-V host performing the role of the on-host backup proxy.
2. The log shipping server and PostgreSQL VM are located in the same network.
3. The log shipping server and PostgreSQL VM are located in different networks (the production infrastructure is isolated from the backup infrastructure).

That is, when choosing a log shipping server, Veeam Backup & Replication will give the top priority to a VM that is located on the source Microsoft Hyper-V host.

Veeam Backup & Replication assigns log shipping servers per job session. When a new job session starts, Veeam Backup & Replication detects a new log shipping servers. Veeam Backup & Replication can also re-detect available servers during the job session. If the log shipping server becomes unavailable for some reason, Veeam Backup & Replication will fail over to another log shipping server.