Drive Read Errors

Polytropon freebsd at
Mon Oct 17 17:45:37 UTC 2016

On Mon, 17 Oct 2016 10:02:28 -0700, Jason C. Wells wrote:
> I have a drive that has always been troublesome. My first indication was 
> that the gmirror would end up degraded and restoring it would be 
> extremely time consuming. (Excuse the terminology, it has been a while 
> since I did that part.) I gave up on the drive and removed it from the 
> mirror permanently.

Good decision.

> I recently used smartmontools long test and discovered that the drive 
> had read errors.
> In your experience, is there any value in trying to use drive by mapping 
> bad sectors or partitioning around the errors?

When those errors start "bubbling up" and become visible to the
OS, it's usually too late. The drive can re-map defective sectors
internally. When it runs out of "spare sectors", the errors are
being processed by the operating system's driver for direct access
storage devices. Those errors usually indicate that the drive has
reached the end of its (useful) life.

The result: When you mark bad sectors (see "man badsect" for details),
you will usually get more and more errors, so you just will see more
problems of the same kind in the future. The drive already is broken.
It's not that _modern_ drives can be "partitioned smaller" and then
continue to work properly for decades. ;-)

Of course there is no problem continuing to use the disk for some
non-critical data, like a scratch disk ("fragile storage"), but the
problems you can expect probably reduce the usefulness significantly.

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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