Works great, until following their instructions corrupts all of your data
Reviewed in the United States on 7 February 2021
I bought the version with 4TB drives and wanted to upgrade to 8TB drives, so I looks up supported drives by model and firmware, and purchased 5 drives, so I would have a cold spare ready to go if anything went wrong.
I followed the process listed here: https://www.qnap.com/en/how-to/tutorial/article/online-raid-capacity-upgrade/
It took about 8 hours to rebuild the array each time, so I just inserted a new drive in the morning before I started work so I could monitor the progress as I worked.
After 3 days, I had gotten 3 drives replaced. I confirmed after each one that my RAID 5 set was intact and completed an integrity check of the Storage Pool and each partition.
Then, on Wednesday morning, I clicked "Replace Disks One by One" as I had with the previous drives, selected the single remaining 4 TB drive, HDD4, which said "You can replace this disk", and clicked "Change". The Description updated to "Please remove this drive", and I pulled the drive. Naturally, the LED on HDD4 went out as expected, and I inserted the new drive.
Then the LEDs on HDD2 and HDD1 BOTH went dark, HDD4 wouldn't light up, only HDD3 was still connected according to the GUI, the status on the RAID 5 set updated to "Failed", the storage pool disappeared entirely, along with all of my partitions, and my externally attached drive disappeared from the list of connected devices. Complete and total failure of the entire NAS on every level.
After spending 4 hours trying to contact customer support and being hung up on by the automated system every 30 minutes, I made the decision to reboot my NAS to get it to recognize the drives again. After reboot, I was informed that the RAID 5 set now only contained HDD1 and HDD2, while HDD3 and HDD4 were not recognized as part of the RAID set.
I again tried calling tech support, and while waiting on them, I removed HDD4 entirely and tried getting it to recognize HDD3. After another reboot, the system once again recognized HDD3 as part of the RAID 5 set, and after an integrity check, stated that the RAID 5 was intact but degraded, so I connected HDD4, and it rebuild the array. Success, or so I thought.
Once the RAID set was rebuilt, it turned out that QNAP recklessly uses a proprietary LVM thin pool variant for their volume management, making it impossible to repair problems with their thin pool using standard LVM tools. While this is a horrifying decision for any company to make, on top of that, they use a thin pool to provision non-thin volumes as well. This manages to combine the metadata corruption vulnerability of thin provisioning with the inability to dynamically provision your space to your volumes.
In short, they spent time and effort to invent completely proprietary drive provisioning that actively puts all of their customer's data significantly greater risk JUST so they can make a new method of volume management that's even worse than anything anyone else has ever created.
This is the consequence of a shockingly incompetent manager making decisions they refuse to understand, and ignoring the advice of their engineers to not create an amateurish drive management system.
Or it's a concerted effort to create a system that will prevent any customer from ever migrating their storage to another platform, knowing that the consequences will be that some of their customer's data will be completely destroyed because they have chosen to use derived but proprietary volume management that hasn't been tested by RedHat, Ubuntu, Microsoft, Amazon, and every other cloud provider.
This hubris of "Let's reinvent the wheel, but make it worse" has led to this colossal failure. While their system MIGHT work for you, the fact of the matter is that if something goes wrong, their custom volume management prevents you from using standard LVM2 tools to repair or retrieve your data, their tiered thin pools utilize non-standard metadata volumes, and they do not provide equivalent tools.
Up until following their instructions TO THE LETTER corrupted all 7 TB of my data, it was a fantastic NAS that I would have recommended to anyone. But the decision to create proprietary volume management only they can fix, that's less stable? That's enough for me to tell everyone I know this:
Never buy a QNAP. They are designed to stop you from ever retrieving your data if anything goes wrong.
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