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How to Use Existing Veeam Backup & Replication PostgreSQL instance for Veeam Backup for Microsoft 365 Deployment

How to Use Existing Veeam Backup & Replication PostgreSQL instance for Veeam Backup for Microsoft 365 Deployment

KB ID:	4638
Product:	Veeam Backup for Microsoft 365 \| 8
Published:	2024-09-03
Last Modified:	2024-09-10

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Article Applicability

This article documents issues that occur when installing Veeam Backup for Microsoft 365 v8 or higher on the same server as an existing Veeam Backup & Replication v12 or higher, with PostgreSQL already present. The errors described may also occur in other scenarios, as they are generic connection errors. The solution provided is strictly relevant to the scenario described.

Challenge

When attempting to use an existing PostgreSQL Instance that was created by Veeam Backup & Replication, the Veeam Backup for Microsoft 365 installer fails with the error:

Unable to proceed due to the following error:
Unable to connect to the specified server. Error: Failed to connect to: <IP>:<port>.

When postgres.conf contains listen_addresses = 'localhost'

Other less common but possible errors are:

Unable to proceed due to the following error:
Unable to connect to the specified server. Error: 28000: no pg_hba.conf entry
for host "<IP>", user " postgres", database "postgres",
no encryption.

Unable to proceed due to the following error:
Unable to access PostgreSQL server using SQL authentication. SQL
authentication is required by backup proxies. Please enable it on the
PostgreSQL server.

Cause

The configuration settings applied to PostgreSQL by Veeam Backup & Replication are incompatible with those required by Veeam Backup for Microsoft 365.

Solution

To enable Veeam Backup for Microsoft 365 and Veeam Backup & Replication to share the existing PostgreSQL instance, you must modify several PostgreSQL configuration files described below.

Part 1: Stop Veeam Backup & Replication Tasks and Services

Ensure all tasks within Veeam Backup & Replication are stopped.
Stop all Veeam services:

Get-Service Veeam* | Stop-Service -Force
                
            

Part 2: Modify PostgreSQL Configuration Files

The default location for all PostgreSQL Configuration Files is:
C:\Program Files\PostgreSQL\15\data\

Edit postgresql.conf and find the setting 'listen_address' and update the line to be:

listen_addresses = '*'

Edit pg_hba.conf and add the following to the bottom of the file:

# non-localhost host with user 'postgres' and SSPI
host    all             postgres        0.0.0.0/0               sspi map=veeam
host    all				postgres		::/0                    sspi map=veeam
# non-localhost host with user 'all' and password
host    all             all             0.0.0.0/0               scram-sha-256
host    all             all             ::/0                    scram-sha-256
                
            

Edit pg_ident.conf and ensure that at the bottom of the file there are:
1. An entry for:
```
veeam   "SYSTEM@NT AUTHORITY"   postgres
```
2. An entry for the user account you will use to install Veeam Backup for Microsoft 365.
  - Domain Account Example:
```
veeam   user@DOMAIN   postgres
```
  - Local Account Example:
```
veeam   user@HOSTNAME   postgres
```
Restart the PostgreSQL Service to apply the changes.

Restart-Service -Name "postgresql*"
                
            

Part 3: Start Veeam Backup & Replication Service and Reattempt Veeam Backup for Microsoft 365 Install

Start the Veeam services:

Get-Service Veeam* | Start-Service
                
            

Reattempt the Veeam Backup for Microsoft 365 install.

More Information

KB4542: "SSPI authentication failed for user"

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