I have been warranty/replace them when the sectors refuse to
reallocate, and/or the disks continue to hit the ERC/TLER timeout all
of the time with bad sectors growing rapidly with no end in sight.

If one is using raid6 and given the low rate of bad sectors, then it
is pretty unlikely that there will be data loss.  If one was using
raid5 things would be more worrisome.


On Mon, Jan 31, 2022 at 1:21 PM Phil Turmel [off-list ref] wrote:

On 1/31/22 14:07, Geoff Back wrote:

quoted

If a disk has one or more bad sectors, surely the only logical action is
to schedule it for replacement as soon as a new one can be obtained; and
if it's still in warranty, send it back.  If the data is valuable enough
to warrant use of RAID (along with, presumably, appropriate backups)
surely it is too valuable to risk continuing to use a known faulty disk?

In which case, I would suggest that dangerous experiments that try to
force the disk to reallocate the block are arguably pointless.

Just my opinion, but one that has served me well so far.

Regards,

Geoff.

I would be surprised if you got warranty replacement just for a few
re-allocated sectors.  The sheer quantity of sectors in modern drives
and the tiny magnetic domains involved means **no** drive is error-free.
  Just most defects are identified and mapped out before shipping.
Reallocations cover the marginal cases.

I replace drives when re-allocations hit double digits, though I've had
to run a few corners cases well past that point.

Phil