/dev/sda slowly dieing??

[Aleksandar Milivojevic]

Roger Grosswiler wrote:
> Hi,
> 
> past days, i had several warnings of my backup, it coudln't read some sectors. Is my harddisc slowly dieing or is this
> another issue? Is there a tool within linux, where i can mark some sectors as defective?

I'd toss the disk.  Marking sectors as bad might sound tempting. 
However, in my experience when you start getting bad sectors, their 
number simply keeps growing exponentially.

Usually what happens inside disk is that you got head crash which 
damaged the surface of disk, and small particle (or several of them) got 
stripped off it.  This can happen because of vibrations, or improper 
disk shutdown (for example, heads were not parked properly for whatever 
reason).  Disks are designed with this in mind, however like with 
everyting, some designs are better than others, and some manufacturing 
facilities are implementing designes better than others (plus 
manufacturers are limited with final disk price and profit margins)...

Since plates are rotating at high speed, this particle(s) will fly 
around all over the inside of the disk.  Because of this, those 
particles are sometimes also called sattelites (rotation of disk is 
making circular airflow, and this particles are light enough to rotate 
with that airflow, like sattelites).  From time to time they will cause 
more damage and occasionally strip more particles from the surface of 
the disk.  Especially if it zips between head and plate, the particle 
can be pushed down to disk surface and may scratch it, plus it can couse 
head vibrations that will lead to another head crash.  What you will 
observer is that your disk is getting more and more bad sectors, and 
their number is exponentially growing.

-- 
Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
Systems Administrator                           1499 Buffalo Place
Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7