Problems rebuilding after disk failure

I have been using a WD EX4100, with 4 WD Red 6TB HDD’s in RAID 5 mode, for five years, no problems at all.

Suddenly, disk nr.1 showed a red light and I got a message that I needed to change the HDD, which I did with a very same WB Red 6TB HDD.

After installing the HDD, the EX4100 started the rebuilding of the volume, this took more than 6 hours.

My problem is that after the rebuilt stopped, I got the message “Rebuilt failure” in the EX4100 display and the red LED for disk nr. 2 lights up steady.

What to do?

Looking forward to hearing good news how to fix this matter!!

Br, Hawkcarl

No good news.

Obviously disk no. 2 has an error too. And: because all disks have the same age, disk no. 3 as well as disk no. 4 soon might fail too.

TODO at least: Backup data. Replace all three remaining old 6TB-disks. Instantiate RAID 5 on those four new disks. Fill that new RAID 5 with the data backed up.

Spending much less time: buy additional EX4100 with four 10TB-disks. Instantiate RAID 10 on that new EX4100. Copy data from old RAID-5-EX4100 to new RAID-10-EX4100.

Hint: replacing one disk, the oldest one, every year by a new one, might cause much less trouble.

Hello Mjoelk (or is it Mjölk?)

The problem is that after replacing the first failed disk, the second hard disk failed during the 5 1/2 hours rebuilding process. Therefore, I CANNOT make a backup since I was using the EX4100 as backup for ALL of my data.

To me, and only me, I think that WD somehow have started PLANNED OBSOLESCENCE for the NAS drives.

FYI, have a Buffalo Link Station attached to me network. This is more the 11 years old and I have 4 WD Green 3TB hard disk installed. I have used this NAS for all the time.

When I Start my PC’s in the morning I start this Buffalo NAS as well, I have NEVER had any problem whatsoever with this NAS.

The reason why I bought the WD EX4100 was that I needed more data storage and Buffalo did not have a suitable product. What a mistake I did.

Now, I have ordered Synology NAS with 8 disk capacity and will install only 14TB disk in the NAS moreover I will install a SDD disk to make sure that the unit work at optimal performance ALL THE TIME.

What can I say???

@dswv42 hints to some papers and articles. According to the contents published there, it will neither suffice to change the vendor nor use more disks to free anyone from the problems, which are intrinsic to disks becoming old and unable to read their stored data.

Under Settings -> Utilities the EX4100 provides a so called “Full Test”. This might detect unreadable data in a disk, before that data is needed for a recovery.

And replacing every disk used in the system at the same time, the producer ends warranty and guarantee, will lift the users security up to the same height, the producer finds necessary for his own well being.

Please recall the content of “Disk failures in the real world […]”. Especially Section 4.2 named “Age-dependent replacement rates”.

That paper is cited in the 2007 ZDNet article you yourself mentioned in post no. 3 of this thread.

I am with you: having one’s data stored in any RAID will not free one from the duty to secure that data by having at least two copies, as fresh as possible and preferably conserved at locations in the world with very large distances to each other and to the source.