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Is it necessary to regularly check drives for bad sectors?

I've heard it's important to do a "full" format when you first get a new hard drive, in order to do a deep chkdsk which will find and mark bad sectors, reallocating them elsewhere. I'm wondering if this analysis should be done on a semi-regular basis -- doing a full, deep chkdsk of drives, in order to keep an eye on bad sectors, and reallocating them if found.

But I've also heard that NTFS does this automatically and continuously, without any user intervention required -- which I assume would make chkdsk an unnecessary redundancy...?

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Just be aware if SMART notes a reallocation by using the Bills answer below. Here is a study of hard drive failures.… While a reallocation does increase the chance of hard drive failure GREATLY, it does not mean it will fail right away. Use the linked study so you can make informed decisions about hard drives and estimating failure rates. Page 7 specifically talks about failure rates associated with reallocation. – Damon Oct 21 '13 at 6:33

Modern hard-drives contain diagnostic mechanisms called S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology). Windows doesn't have a built in graphical utility to access this information (it does have a command-line utility) but you can Google for many graphical freeware programs to do so. Here is an overview and link to such a program. S.M.A.R.T. runs on the drive in the background automatically, all the time. Once you access the information - using a program such as given above - it will tell you the "health" of the drive. If a drive fails a S.M.A.R.T. diagnostic there is no "grey area" it is on its way to failure and you should replace the drive as soon as possible. You don't need to check the S.M.A.R.T. information all the time, checking occasionally is good enough.

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Thanks. I use and monitor SMART attributes, but I believe that SMART only tallies bad sectors that are accessed in some way (read/written), and then increments a flag. I'm wondering if a somewhat-regular full scans of disks should be done to "preemptively" find any bad sectors and have them reallocated elsewhere -- ...or if this is unnecessary and/or happens automatically. – Coldblackice Oct 20 '13 at 18:40
If bad sectors are happening on a hard-drive then you should replace it, once bad sectors start they just get worse. – headkase Oct 20 '13 at 18:55
Reallocated happens automatically, so you don't have to worry about that. Further I agree with Bill, if you find bad sectors, toss the HD as soon as possible. So there is no need to do regularly scans. If you monitor the bad sectors just act on it if it finds some. – Rik Oct 20 '13 at 19:08

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