Zyxel Network-Attached Storage NAS - RAID Managing and Troubleshooting

This article provides a guide to managing, optimizing, and Troubleshooting RAID on a Zyxel NAS. Following this, we explore how to manage RAID volumes within NAS series appliances, including converting basic disks to RAID volumes without formatting, to ensure flexible and efficient volume management. Understanding the inevitability of hardware failure, we then address strategies for handling drive failures within RAID arrays to mitigate data loss and maintain system integrity. Finally, we offer practical instructions for accessing and retrieving data from NAS RAID1 or JBOD arrays using Linux, helping you navigate and recover valuable information from these configurations.

Which RAID should I use?

The NAS326 and NAS520 support RAID0, RAID1, JBOD and BASIC. The NAS540 and NAS542 additionally support RAID5, RAID6, and RAID10.

Following we give an overview of the different RAID types:

• RAID0: Splits data across disks for increased performance but no redundancy. Needs at least 2 disks. Data is lost if one disk fails.
• RAID1: Mirrors data on multiple disks for redundancy but less storage capacity. Needs at least 2 disks. Data is safe if one disk fails.
• RAID5: Stripes data with parity for fault tolerance and better performance. Needs at least 3 disks. One disk can fail without data loss.
• RAID6: Stripes data with double parity for high fault tolerance. Needs at least 4 disks. Two disks can fail without data loss.
• RAID10: Combines striping and mirroring for high performance and fault tolerance. Needs at least 4 disks. Higher cost and lower capacity.
• JBOD: Combines multiple disks into one volume with no fault tolerance. Needs at least 2 disks.
• BASIC: Single-disk volume with no fault tolerance.

More details on the RAID types can be found in this table:

How to create a RAID on a Zyxel NAS

• Open the web interface of your NAS by typing in its assigned IP address in your browser.
• Click on the “Create Volume” notification.
• Choose the “Single volume on RAID” option”.
• Select the desired RAID option, and click next.
• Confirm by "Yes", that every information stored on the hard disks is going to be formatted. This will delete all information on the hard disk saved!
• Click on the summary screen on "apply".
• In the Storage Manager window, click on “Internal Storage”.

Wait until the screen shows you that the RAID creation has been finished.

Available Raid actions

Operations that can be performed without formatting disks are limited to:

• Upgrading from RAID1 (mirror) to RAID5 (striping with single parity)
• Upgrading from RAID1 (mirror) to RAID6 (striping with double parity) in two steps
• Upgrading from RAID5 (striping with single parity) to RAID6 (striping with double parity)

A RAID1 volume can be expanded to RAID6 through an intermediate RAID5 configuration. Conversely, a base disk can be converted to RAID5 by first creating a RAID1 array.

Note: JBOD expansion without formatting is not recommended due to the risk of data loss from interruptions. To safely expand a JBOD array, back up all data, then recreate the array with the desired number of disks.

Converting basic disk to RAID1 volume

• Log in to the NAS WebGUI.
• Open Storage Manager and navigate to Internal Storage > Volume tab.
• Select the desired volume from the list and click Manage.
• Confirm the Change RAID Type task as requested.
• Select the disk to be added to the array and proceed.
• Verify the operation parameters and confirm.
• Monitor the operation status in Storage Manager.
• After the conversion, the screen should reflect the updated RAID configuration.

Converting RAID to higher RAID

• Log in to the NAS WebGUI.
• Open Storage Manager and go to Internal Storage > Volume tab.
• Select the desired volume and click Manage.
• Confirm the Change RAID Type task. Note: Expanding a RAID1 array will create another mirror, which only secures the array by duplicating the drive. This is usually not the desired outcome.
• Choose one or two disks to add to the array and proceed.
• Verify the operation parameters and confirm.
• Monitor the operation status in Storage Manager.
• After conversion, the screen will display the updated RAID configuration.

Drive Replacement Procedure

• Identifying a Failed Drive

Log in to the WebGUI of your NAS. You will be prompted with a warning that the RAID array is degraded. Confirm this dialogue to stop the audible alert.

Go to Storage Manager > Hard Disk to identify the failed drive. It will appear as either failed (red circle) or offline (grey circle) if it's not functioning. Alternatively, check the NAS's LED indicators to identify the failed disk without logging in.

• Replace the failed disk

Navigate to Storage Manager > Disk Group menu. Select the degraded RAID array and click on the Manage button. The only option here would be Repair RAID. Click on the Next button to continue.

Select a new drive to rebuild the degraded array and click the Next button

After the confirmation screen, the rebuild process will start. This may take a long time, depending on the size of the drives. After this process, the RAID array should be back in a healthy state

Failed RAID arrays

When multiple members of a RAID array fail, the array will be stopped and recovery within NAS will become impossible due to data loss. The red danger icon will appear within Storage Manager.

In such a case, removal of the whole array from the NAS is advised. Advanced users might want to try connecting the drives to Linux based PC, creating their images, and examining the array using mdadm tool. If valuable data were stored on the drives, you may as well contact a professional data recovery service, because every recovery attempt on a failed array requires a different approach and this is beyond the scope of this article.

Just a heads-up: Zyxel NAS devices have reached the end of their support period. We understand this might be inconvenient, so to help you out, please visit our forum or explore the NAS section in our knowledge base for all the details. You can also find a list of outdated devices and their support timelines at the link below.

• End of Life (EOL/EoL) / End of Support (EOS/EoS)
• Community Forum Personal Cloud Storage

Thanks so much for your understanding and patience!