I have a HDD that I have reason to believe may be failing, but I'm not really sure.  Right now it is NOT part of the array.  What would be the best way to test the reliability of the HDD?  One idea I had would be to simply add it to the array, but configure all of my user shares to not use that disk.  Then I could just throw random data on the the disk and just let it sit on the array for a while and see if it detects any "reallocated sectors".  Speaking of those, what is considered a "high" number of reallocated sectors for a 1 or 2 TB HDD?  In other words, at what point should I worry?  I have another drive that has 90, but I wasn't sure if that was high or low.

 

The potentially failing HDD in question is already formatted with an UnRAID formatting system (reiser) with some old data.  After I add it to the array I can format it again, right?

 

Thanks!

UBCD has a lot of tools from different manufactures to test an drive.

http://lime-technology.com/wiki/index.php/Configuration_Tutorial#Preclear_Hard_Drives

I have a HDD that I have reason to believe may be failing, but I'm not really sure.  Right now it is NOT part of the array.  What would be the best way to test the reliability of the HDD?  One idea I had would be to simply add it to the array, but configure all of my user shares to not use that disk.  Then I could just throw random data on the the disk and just let it sit on the array for a while and see if it detects any "reallocated sectors".  Speaking of those, what is considered a "high" number of reallocated sectors for a 1 or 2 TB HDD?  In other words, at what point should I worry?  I have another drive that has 90, but I wasn't sure if that was high or low.

 

The potentially failing HDD in question is already formatted with an UnRAID formatting system (reiser) with some old data.  After I add it to the array I can format it again, right?

 

Thanks!

jonathanm already gave a good answer. I just wanted to chime in and say that your idea is a really bad one. Adding an untrustworthy drive to your array puts all your other drives at risk since if one of the other data drives fails it requires parity plus all the other data drives including the untrustworthy one to rebuild the failed drive.

I have a HDD that I have reason to believe may be failing, but I'm not really sure.  Right now it is NOT part of the array.  What would be the best way to test the reliability of the HDD?  One idea I had would be to simply add it to the array, but configure all of my user shares to not use that disk.  Then I could just throw random data on the the disk and just let it sit on the array for a while and see if it detects any "reallocated sectors".  Speaking of those, what is considered a "high" number of reallocated sectors for a 1 or 2 TB HDD?  In other words, at what point should I worry?  I have another drive that has 90, but I wasn't sure if that was high or low.

 

The potentially failing HDD in question is already formatted with an UnRAID formatting system (reiser) with some old data.  After I add it to the array I can format it again, right?

 

Thanks!

jonathanm already gave a good answer. I just wanted to chime in and say that your idea is a really bad one. Adding an untrustworthy drive to your array puts all your other drives at risk since if one of the other data drives fails it requires parity plus all the other data drives including the untrustworthy one to rebuild the failed drive.

Ok yeah, thanks for the sanity check.  I guess I'll just have to stick it in my desktop PC as a secondary drive to test it out.

There's nothing wrong with leaving the drive in your unRAID machine as long as it's not part of the array. So long as the drive is not part of the array, it won't impact your array and you can run the preclear script to pound on the drive and see if it breaks or gives you any info.

 

If you're not clear on this, it might be best to plug it into your desktop and run a manufacturer test tool on it.

In fact, if you think you might want to add it to the array if it passes the test, then preclear is what you should do, since it needs to be clear to add it.

There's nothing wrong with leaving the drive in your unRAID machine as long as it's not part of the array. So long as the drive is not part of the array, it won't impact your array and you can run the preclear script to pound on the drive and see if it breaks or gives you any info.

 

If you're not clear on this, it might be best to plug it into your desktop and run a manufacturer test tool on it.

Oh ok, I didn't realize you could start your array without all the drives assigned.  I will read up on this and try it out.  Thanks.

I just want to re-ask one of my previous questions that didn't get answered: what is considered a "high" number of reallocated sectors for a 1 or 2 TB HDD?  In other words, at what point should I worry?  I have another drive that has 90, but I wasn't sure if that was high or low.

 

I noticed under the SMART attributes for that drive that it has a line for reallocated sector count and it is orange in color.  But it says "never" under the "failed" column so does that mean I should watch that status to see if it is getting too bad?  I also noticed that the "value" column says 98.  Does that mean the drive can only go up to 98 before it starts potentially losing data?  If so, that seems like I'm really close...

 

Thanks.

Mod's - maybe to make it clearer to those who come to the forum rather than the Wiki (and I don't blame them sometimes) maybe we should have a Sticky similar to the title of this thread in General Support.

 

Test the reliability of your HDD's before deploying them and adding Data

 

It's amazing how much it comes up. Happy to write it if you like?

Mod's - maybe to make it clearer to those who come to the forum rather than the Wiki (and I don't blame them sometimes) maybe we should have a Sticky similar to the title of this thread in General Support.

 

Test the reliability of your HDD's before deploying them and adding Data

 

It's amazing how much it comes up. Happy to write it if you like?

Sorry for the confusion, because this question was tangential to the thread's subject.  I'm asking because I have another disk that is already part of the array and is currently being used that has these reallocated sectors.

 

edit: P.S. I see in the wiki where it talks about monitoring a drive that has a reallocated sector count above 0 (which mine obviously does).  But since I just installed UnRAID v6 I never saw the SMART alerts until now and so I haven't seen how often the count increases on this drive.  Based on what is implied in the wiki I'm guessing 90 is "high" but I wanted to be sure before I rushed out and bought another drive (since this one is still working and UnRAID hasn't made it RED yet).

I just want to re-ask one of my previous questions that didn't get answered: what is considered a "high" number of reallocated sectors for a 1 or 2 TB HDD?  In other words, at what point should I worry?  I have another drive that has 90, but I wasn't sure if that was high or low.

Modern drives come with hundreds of spare sectors, typically from 600 to 4000, all empty and unused and ready to swap in.  That's the way manufacturers make them, because they expect a few sectors to go bad.  Occasionally a few are found to be bad within the first month, a good time to find and replace them.  Then you should rarely find any more bad sectors until the drive starts to fail.  Which is why users become concerned when a new crop of bad sectors shows up - is it an anomaly or is it the beginning of the end for that drive.  The best practice for that situation is to save all data off it, then test it thoroughly and try to make it fail.  If the drive is good, there should be no more bad sectors, no matter how hard you test it.  If the drive is failing, then the bad sectors will continue, the reallocated sector count will continue to grow, and you can no longer trust the drive, and should trash it.

 

That's why the question is not if a certain number is good or bad, but whether it is growing or stable.  90 is probably more than you would like, but if it never changes, then the drive still has more life in it.  If you start seeing 91, then 93, then 94 etc, then you know you have a problem, need a replacement.

 

I noticed under the SMART attributes for that drive that it has a line for reallocated sector count and it is orange in color.  But it says "never" under the "failed" column so does that mean I should watch that status to see if it is getting too bad?  I also noticed that the "value" column says 98.  Does that mean the drive can only go up to 98 before it starts potentially losing data?  If so, that seems like I'm really close...

The 98 is a scaled value that runs from 100 down to 1, so 98 means it has only dropped 2.  That implies there are many more spare sectors available.  Not that you would want to use them, because if it is starting to use them up, then the drive is probably starting to fail.

@RobJ  Awesome, that makes complete sense.  Thank  you.

Mod's - maybe to make it clearer to those who come to the forum rather than the Wiki (and I don't blame them sometimes) maybe we should have a Sticky similar to the title of this thread in General Support.

 

Test the reliability of your HDD's before deploying them and adding Data

 

It's amazing how much it comes up. Happy to write it if you like?

 

I've been very impressed with your work!  Great answers, complete with good detail, and I especially appreciate the respectful tone.  Anything you want to write will be greatly appreciated, and I'll be happy to sticky it!