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How to recover your expansion unit after replacement or disconnection?

Introduction & Feature

As QNAP expansion units help you expand the capacity of your NAS for further storage and backup needs, it is important to be able to quickly recover the unit if you encounter an abnormal situation. Storage Manager has various built-in functions to help quickly recover both the expansion unit and the data. This article provides the following examples:

1. The expansion unit loses connection to the NAS or is accidentally powered off and needs to be reconnected and recovered.
2. The expansion unit was changed after a hardware failure but contains hard drives used previously.
3. The expansion unit in the middle of a chain is disconnected, how to reorganize the enclosure ID.

Audience

This application note is suitable for anyone responsible for managing a QNAP NAS with expansion units in personal or business environments.

1. How to Start

1.1. System Requirements

The Recover Enclosure and Reinitialize Enclosure ID functions described in this document are available in QTS 4.1.3 or above, while "Safely Detach" is only available starting from QTS 4.2.

2. Reconnect an expansion unit

2.1. Lost connection or power

If the expansion unit is accidentally disconnected from the QNAP NAS or if it loses its power, the Storage Manager will display an error icon in the Overview Section, and in the Disks sections the expansion unit will be marked with a disconnection icon to indicate that this unit is in "Missing Mode". In this mode, while you cannot use File Station to view the contents of the missing expansion unit, you also cannot directly remove the expansion unit. This mode is used to ensure data integrity once the unit is restored.

In the Overview, an error icon will be displayed in both the Disks and Volumes section. In this example, the REXP1 is disconnected.
The disconnected icon will be displayed in the Disk section to warn that the expansion unit is in "Missing Mode" and no longer at work.

To recover the expansion unit, check that the expansion unit is powered on and correctly physically connected to the QNAP NAS. If the expansion unit is correctly reconnected, the system will automatically display a recovery message. After confirmation, click "OK" to start the recovery process. You can also do so in the "Disks" section of the Storage Manager by clicking "Recover" and selecting "Recover Enclosure".







The system will automatically detect if an expansion unit has been reconnected.
Or you can click "Recover" > "Recover Enclosure" to reestablish the connection between the NAS and expansion unit.

After the Storage Manager has completed the recovery process, check to see if the error icon has been removed from the "Overview" section and File Station. If so, you can now access the expansion unit's volume again.

Review the Overview section and File Station to see if the expansion unit is now back to normal status.

3. Recover data in an expansion unit with a hardware failure

3.1. Change an expansion unit (USB Bus Type)

If the expansion unit experiences abnormal issues but the hard drives are not damaged, you can move them to a different expansion unit and connect this new unit to the NAS. To do so: power off the expansion unit, unplug it, remove its hard drives, reinsert them into another expansion unit according to their original order, then power on connect the new expansion unit to the NAS.

*The replacement expansion unit must have the same or more number of hard drive bays. To avoid any unforeseen errors, it is recommended to use the same expansion unit model.

An expansion unit encounters an abnormal condition and is not recognized even when connected to NAS.
All of the storage pools on the expansion unit, even partially, will be unavailable until recovered.

After the new expansion unit is plugged into the NAS, two expansion units will appear. To remove the old abnormal one from the system and allow the new expansion unit to replace it, click "Recover" in the top right of the window and select "Reinitialize Enclosure ID" (this requires a NAS reboot). This allows the QNAP NAS to reorder all of its expansion units. After this process is completed, the replacement expansion unit will be reassigned to "REXP 1" and the abnormal expansion unit replaced.

*You may be prompted to scan the new expansion unit for existing storage pools/volumes. This action is not needed when replacing an expansion unit. If it appears, you can safely click "Cancel".

Select "Reinitialize Enclosure ID" to allow the new expansion unit to replace the abnormal one.

After the system reboots, you will see that the storage pools are back to normal.

All the storage pools and volumes are back to normal.

3.2. Change an expansion unit in the middle of a chain (SAS)

"Reinitialize Enclosure ID" can also be used to replace an expansion unit that is in the middle of a chain. In this example, we have 5 expansion units that are chained one by one via SAS bus and the expansion unit REXP#3 has a hardware failure and needs to be replaced.

There are 5 expansion units that chained one by one via SAS bus
As the expansion unit REXP#3 shuts down, all of the following expansion units enter "Missing Mode" for protection
The storage pools located on REXP#3 (and after) are unavailable. Missing mode protects the data against any access.

To replace REXP#3: disconnect it from the rest of the expansion units, power off the expansion unit, unplug it, remove its hard drives, reinsert them into another expansion unit according to their original order, and then reconnect all the expansion units to the new expansion unit as the old one was connected. In Storage Manager you should see a new expansion unit REXP#6. Select "Reinitialize Enclosure ID" in the Recover dropdown menu to redistribute the ID of expansion unit and reboot your NAS.

*The replacement expansion unit must have the same or more number of hard drive bays. To avoid any unforeseen errors, it is recommended to use the same expansion unit model.

REXP#6 appears after you connect the new expansion unit to REXP#2
Select "Reinitialize Enclosure ID" in the "Recover" menu

After rebooting, you will see that REXP#6 has changed to REXP#3, while at the same time REXP#4 and REXP#5 still function normally.

After selecting "Reinitialize Enclosure ID", you will need to reboot the NAS.
All of the storage pools and volumes are back to normal after the recovery process

3.3. Change an expansion unit in the middle of a chain (Thunderbolt)

The process of recovering an expansion unit in the middle of a Thunderbolt chain is similar to the previous SAS process. To replace an abnormal Thunderbolt expansion unit in a middle of a chain: disconnect it, power off the expansion unit, unplug it, remove its hard drives, reinsert them into another expansion unit according to their original order, and then reconnect all the expansion units to the new expansion unit as the old one was connected.

When the new expansion unit powers on, you will be prompted to recover the expansion unit. Click "OK" to confirm and after this the data in the original expansion unit will be recovered.

When moving hard drives to a new expansion unit and connecting that unit according to the original order, a recovery message will appear.
After the recovery process, the volume is back to normal. ("Reinitialize Enclosure ID" is not needed for Thunderbolt).

3.4. Permanently remove an expansion unit

3.4.1. QTS 4.1.x

"Reinitialize Enclosure ID" allows you to reorganize the REXP ID if needed in QTS 4.1.x. For example, if you want to remove a specific expansion unit in the middle of the chain, remove all the volumes and storage pools that are located on this expansion unit and then disconnect it. After rebooting, the disconnected expansion unit will not be displayed in the Storage Manager, and the ID of expansion unit will be redistributed.

Using "Reinitialize Enclosure ID" to remove expansion units that have been disconnected from the QNAP NAS.

3.4.1. QTS 4.2.x

If your QTS version is 4.2 or above, in "Storage Manager" you can select an expansion unit you want to remove, and select "Action" > "Safely Detach". This action will allow you to safely and directly remove an expansion unit from a chain and connect the expansion to another QNAP NAS. For more information on using this function to conduct data migration, please refer to the application note "Use JBOD migration".

*The function "Safely Detach" is only available in QTS 4.2 or above

Select "Safely Detach" to remove an expansion unit from a chain without removing its hard drives.
Release date: 2015-09-09
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