So-called low level formatting, or writing zeros to every accessible sector of the drive to reallocate the sectors from less reliable parts of the disk would not work because when the drive runs out of reserved sectors it changes the way it handles errors in a way that makes it much less convenient to use than a traditional drive that does not do any predictive failure analysis and simply reports an error.TLDL: Its a commericial piece of software attempting (and failing) to analyze the output from the free software already included in unRaid. When the firmware thinks it cannot cope with the errors, it makes the drive unusable.īy running the value of reallocated sectors down to 02 I conclude that there are 2048 reserved sectors on this drive. When the old drives let the software keep track of bad blocks and avoid using them, modern drives do not give this opportunity. The drive returns out of the blocked mode only after powercycling the drive. In this situation the firmware just blocks the drive. This means that the drive might have reserved sectors, yet a part of it may run out of sectors to remap. To explain this behaviour as David Schwartz suggested, I assumed that reserved sectors are somehow distributed over the address space of the drive. Even though the value of reallocated sectors was still positive. That is every ATA command, even IDENTIFY DRIVE returned ABRT. Then after a single error the disk turned itself into a blocked mode. This can be explained by the fact that certain RAID houskeeping data was stored at the beginning of the disk, therefore the wear in the small addresses area was higher than in the rest of the disk.
Then from the first 10G to 700G there was no change. I observed that there was a sharp rise in the number of reallocated sectors when writing to the beginning of the disk. To test the drive I ran badblocks -wv with the default blocksize and monitored the reallocated sector count in the process. In short, there is no easy way to get the list of reallocated sectors and even statistical methods of mapping the disk are heavily encumbered by the need to play against the logic of the firmware. I'd like to thank you for the advice and share some of the details that I've got from experiments. I am thinking of giving a second chance to the better parts of the platters. We get a few of them failing every year and just throwing them away seems to be a waste. Is there a way to recover the list of reallocated sectors?Įdit: This drive is from an array.
However there are no badblocks visible to the operating system. In order to create such a partition it is necessary to fetch the list of remapped sectors. Instruct the operating system to not use that partition. Is to create a disk partition over the region which contains remaps and A workaround which will preserve drive speed at the expense of capacity Wikipedia article suggests that the drive can still be used for less sensitive purposes like scratch storage outside of an array if remapped sectors are left unused. After 3 years in 24x7 service a 1TB Seagate Barracuda ES.2 enterprise drive is showing signs of failure.