Knowledge Base

Search by either entering keywords or by selecting a product.

Configuring Failover on Buffalo TeraStations


What Is Failover?
With failover, two TeraStations are connected to the network for redundancy. If a problem occurs in the main TeraStation that causes it to become inaccessible, operation is automatically switched to the backup TeraStation.

In order to configure failover, certain conditions must first be met:
1.    The TeraStations must be identical models and have identical capacities. If the capacity of the main TeraStation is larger than that of the backup TeraStation, configuring failover will cause an I33 error to occur.
2.    All drive bays of a TeraStation should be occupied if it will be used for failover. Failover will not work if a drive is missing from any bay.
3.    Use static IP addresses for both TeraStations. Because the IP address of the TeraStation designated as the backup cannot be changed, set its IP address before configuring failover. For more information on configuring static IP addresses see here.

Usage Restrictions
Failover cannot be set up if any of the following functions are enabled:
Replication, sleep mode, encrypted disk volume, MySQL server, media cartridge, LVM volume, iSCSI volume, port trunking, cloud storage, surveillance server, hot spare, access restrictions by Active Directory or NT domain

The following operations will not be available while failover is enabled:
Initializing settings, changing the RAID settings, formatting drives, iSCSI volume, changing the backup unit's settings

Non-Transferable Settings
The settings below are not copied from the main TeraStation to the backup TeraStation. Make a note of the original settings so that they can be configured manually if the backup TeraStation replaces the main TeraStation.
Web server (including PHP), MySQL server, Direct Copy, WebAccess, print server, UPS synchronization, antivirus (using the native TeraStation antivirus)

Using with a UPS
Once failover is configured, you cannot set up UPS sync for the backup TeraStation. Configure your UPS before configuring failover. UPS recovery can be configured for both the main TeraStation and the backup TeraStation. However, the UPS settings of the main TeraStation will not be copied to the backup TeraStation.

If the backup TeraStation is configured to sync with the UPS connected to the main TeraStation, and the main TeraStation shuts down, the backup TeraStation will no longer be able to detect if there was a power outage. In this case, move the UPS communication cable from the main TeraStation to the backup TeraStation and reconfigure the UPS link settings.

There are two options for failover cabling: using LAN port 1 only or using both LAN ports.

Using LAN port 1 only

The backup TeraStation is updated over normal network traffic.

Using both LAN ports (Preferred)

With the second setup, the backup TeraStation and main TeraStation are connected by a second Ethernet cable connecting their respective LAN 2 ports. Updating is done over this dedicated network path, so updates are quicker and don't interfere with normal network traffic.

In both configurations in the event of a failure the backup TeraStation will assume the name and IP addresses of the primary TeraStation unless a "Service IP" is configured in the failover setup.


1.    Access TeraStation's Settings and click on the "Backup" tab from the left hand column.
2.    Click on the configuration icon to the right of "Failover".
3.    Click Edit Failover Status in the upper right corner to start failover configuration.

4.    Choose the correct backup TeraStation from the drop-down menu. If you used cabling method 2 above, choose the "LAN 2" for the Backup LAN Port.

5.    Enter the admin password for the backup TeraStation then click Continue.

6.    If the administrator password is correct, the backup TeraStation will beep. To accept the settings from the main TeraStation, press and hold the function button on the front of the backup TeraStation until it stops beeping.

7.    The following screen appears on the primary TeraStation until failover is fully operational. Wait until initialization finishes. The amount of time required will vary depending on the amount of data already stored on the primary TeraStation.  (I51 message will display on the LCD panel and NAS Navigator2 for both TeraStations.)

8.    Both TeraStations will appear with informational alerts in NAS Navigator until the process is finished.  

9.    Failover is configured after it finishes and the I51 message disappears on the TeraStation LCD.

10.    Once the process is complete the primary TeraStation will show a status of "Normal (Main Device)" in the Failover section of Settings. Failover is now configured.

11.    Access Settings for the backup TeraStation. The following screen appears. At this point, the backup TeraStation's Settings page will not be accessible without stopping failover. Click Log Out and exit Settings for the backup TeraStation.

Please note that the RAID array on the backup TeraStation may be reconfigured and resynchronize as part of the failover process. This is expected behavior and not an error.