HDD Low Level Format and Bad Blocks

[BlueSky]

Hi,

I have a couple of ST4000NM0053 4GB Enterprise drives that I have pulled from a QNAP NAS because there was an increase in SMART errors from 0 to 7 in one particular area, sectors I believe. I ran the QNAPs block by block check on the disk and it found five bad blocks.

My question is will the low level format detect and lockout any bad sectors so that the OS can longer see these bad spots and stop trying to use them?

Thanks much!

Joe

[abolibibelot]

Strange that noone bother to reply...
Yes, normally bad sectors are reallocated during a write operation, so a so-called “low level format” (which is an improper name), by overwriting every single sector of the drive, will force the reallocation / remapping of any bad sector encountered (or clear it if it turns out that it was in an inconsistent state but still functional – it happens for instance in case of a sudden power cut, but it's rare, most of the time a bad sector is “really”, as in “physically” bad and not fixable). But a drive with as few as 5 confirmed bad sectors should be used with great caution – it could stay stable for years, but it could worsen quickly and result in data loss.