[vox-tech] Bad blocks on my hard drive

[Bill Broadley]

On 05/24/2011 05:30 PM, Chanoch (Ken) Bloom wrote:
> I discovered bad blocks on my laptop hard drive today -- the laptop is
> nearly 6 years old. I ran e2fsck -c the drive to mark the bad blocks as
> bad, and everything seems to be working now.

That helps, on older drives.  Not sure when the transition was, but at
some point around then drives started silently remapping sectors.
Basically it would have some hidden spare capacity.  Then if it saw
errors (only on writes, never on reads) it would remap that to a hidden
sector.

Customers like this because it looks like they have a "perfect" drive.
Manufacturers like this because they don't get annoyed by customers
saying I bought a new drive and it says X sectors are bad.

Basically it's cheaper to make a 2TB drive with 1% spare hidden capacity
and less than 1% error rate than it is to make a 2TB drive with 0% spare
capacity and 0% error rate.

With one of the remapping capable drives once you see sectors that don't
clear on write then typically the drive dies pretty quick.

For the older drives that can't remap it can be anywhere between 0 time
to death and until you stop using the drive for other reasons.

Often even with a trashed filesystem because of bad sectors a reformat
(on new drives) or a badblock scan (on old drives) and the disk will be
usable for at least a little while and sometimes quite a long time.

Speaking of whic most drive manufactures have a drive test utility that
will analyze your drive and give it a pass/fail.  The short test is
often a minute or two, but the long test takes hours and is a better
measure of health.

Certainly if you have anything of value I'd suggest regularly backups
with or without such errors.

> How long do I have before I need to replace the hard drive and/or
> laptop?

Impossible to guess.