About hdd URE, I knew these points:
- For some reasons, when harddisk reading a sector that the FEC(Foward Error Correction data) could not correct the errors on that sector, we encontered an URE.
- The rating we encountered an URE is very low, but still exists.
- When reconstructing a RAID 5 array, sometimes it will happened and the reconstruction progress will stop.
But I still have some questions:
- If there is a single disk, what will happened? Hardware/file system report an error and we lost a file? Or we got the file with wrong data?
- Will rewrite some data to that URE sector could turn the sector become normal? Or must we use some utilities provieded by HDD manufactory and remap another reserve sector?
- If it happened when we mirror/re-mirror a RAID 1/10 array, what will the RAID controller do? Stop the mirror progress? Or just copy the uncorrect data to another disk?
Thanks for the answer, question 1&2 is solved.
But the 3rd question I mean if encountered URE when converting a single HDD to RAID 1 array by add another new disk, or replacing a failure disk in a RAID 1/10 array, there's no redundancy to correct the error. Will it complete the mirror/re-mirror progress with error data? OR stop the progress like RAID 5 recontruction?