Knowledgebase: RAID Management
The RAID was lost, what should I do?
Posted by - NA -, Last modified by on 19 April 2011 10:53

[About RAID Lost]

When a RAID-1 / RAID-5 / RAID-6 / RAID-10 lost a disk, the RAID status will change from healthy to degraded.

In general to say, RAID-1 array has mirror in every disk, you may read out the data from every disk if the file system is clean. A RAID-5 only allow one disk left, once two disks left the RAID-5, the RAID was broken. RAID-6 allow two disks left, once three disks left the RAID, the RAID was broken. After the RAID was broken / damaged, for the models that come with LCD may show "RAID: N/A" on the LCD.

Since JBOD and RAID-0 give you no redundancy, even only one disk left the RAID will lead the RAID to damaged and can not be rescued.

For RIAD-10, it was built as disk#1 and disk#2 for RAID-1 mirror pair, disk#3 and disk#4 for RAID-1 mirror pair, and then assemble two mirror pairs as RAID-0. Therefore if both disk#1 and disk#2 left the RAID, or both disk#3 and disk#4 left the RAID, it will damage the RAID and can't be rescued. If only one disk left every mirror pairs, for example, disk#1 and disk#3 left the RAID, the RAID status was changed to degraded. Compare RAID-10 with RAID-6, the latter can tolerate any two disks dropped out of the RAID. So RAID-6 is better than RAID-10 from the point of data safety.

Besides RAID was damaged, there is another reason that shows "RAID: N/A" due to the file system error. If the file system is not clean, Thecus NAS will not mount the file system and will disassemble the RAID, that is another reason that you may see the "RAID: N/A" message.

Here are some articles for your reference before we could go through,

What is S.M.A.R.T.

Why my disk shows warning even after bad block scan?

How to rebuild a degraded RAID?

[Important Information]

Before contacting Thecus staff, 

1. Do NOT create a new RAID. According to the feedback from our customers, some user might re-create a new RAID because they assume the RAID will back after they "create" one. Once you create a new RAID, the original raw data will lost forever and can not be rescued.

2. Do NOT run file system check only if you know what you are doing. We recommend user doing this after cloned all disks, running it at cloned disk and keep the original disks on hand. Since file system checking will write to disks physically, once it failed, you still keep your original disks.

3. Do NOT try to reboot and reboot. If RAID was damaged, reboot won't help. Sometimes it might make it worse.

4. Do NOT try to plug in / out the disk, or change the tray. Keep the environment is the best way.

[Download NAS Configuration file]

Before contacting Thecus staff, please download NAS configuration file (conf.bin),

* x86 Firmware v2.xx.xx

It can be downloaded from [System / Config Mgmt] and then press [Download] button.

* x86 Firmware v3.xx.xx & x64 Firmware v1.xx.xx

It can be downloaded from [System Management/ Utility/ Config Mgmt] and then press [Download] button.

* x86 Firmware v5.xx.xx & x64 Firmware v2.xx.xx

It can be downloaded from [System Management/ Config Mgmt] and then press [Download] button.

After download the conf.bin, please submit a ticket on our support system and attach the conf.bin file. We might know more detail information, if possible please also provide the RAID level, file system and so on.

[Clone the disks]

In most cases, we recommend user to clone all disks, please refer to

[Publish your NAS on internet]

Thecus staff may also need to check the NAS remotely, please select one of the following methods to publish your NAS on the internet.

A. Public Fixed IP (most easy)

Just assign a public fixed IP on the NAS WAN port

B. DMZ (easy)

Enable Router DMZ function and fill in NAS WAN private IP in the Router DMZ column, and then tell me the router WAN IP.

For Example:

Router WAN IP is

Enable Router DMZ function and fill in for DMZ, thus the Router will forward all connection of from internet to NAS WAN IP, than I could access to the NAS.

C. Virtual Server (port forward) (a little difficult)

Assign port 22 and 80 (or 443) forward to NAS private IP, we also need the admin password to login, please change a new admin password and let me know what it is.

For method B and C, we also have a quick guide for reference,

*** Backup is always the best way for data safety ***

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