Bad sectors on a HDD

Posted on 2011-09-13
Last Modified: 2016-06-26
Hi everyone,

We order 9 "Top Grade" 2TB HDD Enterprise Storage from Western Digital and 6 out of 9 have bad sectors. Most of them have 2-6 bad sectors, and a couple had around 50 bad sectors. We used HD Tune to test these HDD over eSATA and also USB

Is it normal to get 2-6 bad secotors?
are there other more effective ways of testing the HDD?

Thank you, and I'll be waiting for your response.
Question by:Kaptain1

Accepted Solution

inetman earned 167 total points
ID: 36533390
it is not normal to have bad sectors when you get new hard drives.. That why we have warranties. send them back to your supplier and get replacements.
LVL 30

Assisted Solution

by:Duncan Meyers
Duncan Meyers earned 166 total points
ID: 36533505
I have to disagree: it is 100% normal to have bad sectors. There is a chunk of storage on every drive that is used specifically for remapping bad sectors - this remapping happens "under the covers" and you typically won't see it occur. You will see a classic bad sector in the host operating system if the drive cannot recover the data and remap the bad sector. Again, typically, you won't see bad sectors unless the remap area is exhausted - but if that happens, the chances are that the drive is expiring.


Assisted Solution

inetman earned 167 total points
ID: 36533508
During formatting a disk, the operating system may identify any bad sectors on the disk and marks not be used. If you find any bad sectors, data becomes damaged; the hard disk is reporting one or more of sectors are bad. This may be on a new drive, or there may be bad sectors showing up on a drive that has been in a system for a while. The bad sectors are generally a real problem with a hard disk and usually imply a legitimate problem with the hard disk itself.

A new hard disk should have zero bad sectors on it. An older drive may grow a bad sector in many cases this is a harbinger of impending disaster with the disk. The steps below discuss possible problems that can lead to a bad sector showing up. In addition to trying to eliminate the cause, you also should contact your hard disk manufacturer's technical support department and inquire about a utility to remap the bad sector so it is hidden and replaced with one of the spares on the disk.

As soon as you find any bad sectors this is an indication that the disk must be made back up immediately, or you risk possible loss of your data. In order to avoid any significant changes to the software setup on the drive, or adding any new data to it, until you get the situation resolved. Make sure that you are not using an IDE cable that is too long. The specified maximum is 18 inches, but some drives need them to be even shorter than that to work properly. Try replacing the cable with a shorter one, if possible. If you are getting bad sectors on more than one disk in the system, or even after replacing the disk, then the problem lies somewhere other than the disk, most likely. It could even be bad power from the power supply.

Some hard disks have firmware problems. In this case the manufacturer may make a firmware upgrade available for the disk; this is like a flash BIOS upgrade for your hard disk (except it is easier to install and is used only for fixing bugs). Check your manufacturer's web site for more information on this possibility. I know for example that this has happened with some of Western Digital's Caviar series hard disks and in many cases the firmware upgrade resolved the problem nicely. If you do and are still getting more bad sectors showing up, the drive should be treated as imminently failing and you should contact your manufacturer's or system vendor's technical support department.

If the drive is new or the system is still under warranty, insist on a replacement drive. See here for more. There is no reason for a new hard disk to have bad sectors on it, period. Don't let them try to convince you otherwise. If you have a drive out of warranty that gets one or two bad sectors, then if you feel comfortable with the drive, map out the bad sectors and continue using it. In some cases, there is just one weak area on the disk, and the rest of it will continue to be quite usable for some time. However, if the number of bad sectors is large or is increasing in time, look out, because the chances of the drive failing outright become much higher when this happens. These bad sectors are responsible for loss of the data from the drive. The major reasons for the development of bad sector on hard drive is due to improper shutdown and voltage fluctuations which may be the general cause for the bad sectors.

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LVL 30

Assisted Solution

by:Duncan Meyers
Duncan Meyers earned 166 total points
ID: 36533672
There is a world of difference between a bad sector reported during a drive format and a bad sector/relocation reported by the drive firmware or SMART. Bad sector relocations are normal and can be ignored unless they're increasing rapidly. Bad sectors reported during an OS format are another matter entirely - and if you see them, then get the drive replaced.
LVL 91

Assisted Solution

nobus earned 83 total points
ID: 36535469
what you can do is run HDDRegenerator on it -  it has repaired several disks for me -none came back      

as a matter of fact - i run it on all my spare disks
LVL 69

Assisted Solution

Callandor earned 84 total points
ID: 36535860
Bad sectors are normal on drives - you just don't want one where the number increases in a relatively short amount of time.  As meyersd said, the drive handles the marking of these sectors as bad so that they are not used, and this happens without you knowing about it.

Author Closing Comment

ID: 36553007
Thank you everyone for your fast reply. I will take all your answers under consideration.

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