What happens in case of URE when recovering ?

MrPhelps wrote:

Yes, URE is an Unrecoverable Read Error, which means one bit of data irremediably lost. I'm not sure how they're related to the pending sector count, which may or may not be recovered, or remapped to other sectors. I'd like to know specifically for the ReadyNAS NV+ implementation of X-RAID, does this result in a failure of the whole array, or only a stripe ? (I understand that determining which files are affected is not easy, and that's the job of the filesystem anyway).

Sectors are not reallocated ("remapped") on a read error, that is only done when a write fails. When a read fails, the pending sector count is incremented.

More to your point, there is an old post on the subject:

yoh-dah wrote:

snowman136 wrote: Sooo ... if I understand you, a RAID5 or x-RAID array can rebuild the array after a drive completely fails AND there are some bad spots (unrecoverabe read errors) on the reamining drives. Not exactly. If there's an unrecoverable error on the 2nd disk, the ReadyNAS will go into 'life-support" mode and prevent any more I/O to the data volume. If for some reason the 2nd disk refuses to join in the RAID volume, it's often possible to do so manually, but this requires some expertise and is not automatic.

I am not sure if that information is still correct, or if it applies to all platforms (this quote is from 2007). Hopefully one of the jedi will comment.