QNAP NAS Community Forum

Bad Block Scan completed and reports 15 bad blocks found. Is there a tool that can repair them? How worried should I be? 1 of 3 6tb WD red drives in bays 1-3 of a TVS-471. Thanks!


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RAID scrubbing would repair them, but do you really want to trust any HDD with bad blocks ? .. what if another drive fails ? (rebuild from defective blocks will not work)

I'd replace it sooner rather than later

dolbyman wrote:RAID scrubbing would repair them, but do you really want to trust any HDD with bad blocks ? .. what if another drive fails ? (rebuild from defective blocks will not work)

I'd replace it sooner rather than later

Thanks... I’ll scrub for now and see about getting some new drives. I am out of the US and getting drives is a long slow process. I currently have slots 1-3 configured as RAID5 using 3 WD 6tb drives. Slot 4 is a separate stand alone drive. Is there a good doc or simple instructions as to how to swap old for new drives without loosing data/configurations. I have only done the initial build, several years ago, and never upgraded or needed to swap drives. Thanks!


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the online manual explains it pretty well

TL:DR hotswap a new drive (of equal or larger size) and rebuild will start automatically

From what I know HDs have several reserved tracks for Bad Blocks.
Does SMART 197, 198 errors mean "no more reserved tracks" to substitute bad blocks?

How frequent should we do Scrubbing? From my understanding, we should at least do this once a week, and immediately upon Bad Block discovery. But what is the best practice?

And lastly, what exactly does QNAP do during RAID Scrubbing? And how does it recover errors?

Thanks.

If the HDD hits a bad sector during a read and it can't recover from it via the CRCC, then there is no getting that data back, period. The unrecoverable error should be logged by the NAS. That HDD needs to be replaced immediately. Recoverable errors are a bad sign, indicating that the HDD is going to end up failing. Get it replaced immediately.

Just takes time, effort, and additional cost when living outside of the world of Amazon, tech stores, and easy access to things...


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