Hot-swap Won’t Recover Your Crashed RAID 5 Data
If you think the way to recover RAID 5 arrays that have crashed is to replace the bad drives with good ones, you have missed some fundamental points about RAID 5 and more importantly the extent of the data disaster you now face.
RAID 5 is one of a number of RAID levels that relies on the existence of parity striping to provide data redundancy distributed among however many drives (at least three and sometimes as many as twenty or more). This is initially calculate by the RAID controller which is then responsible for generating updated values for the party blocks as data is updated by users or files moved or deleted.
RAID5 is designed to allow any single hated drive in the array to fail – it can get past this without any user perceiving that there is a problem – the RAID controller keeps the show on the road by using the remaining drives to work out what would have been contained on the failed drive. So when a RAID 5 fails, it means that there are intractable problems on multiple drives – that is not something you can resolve with simple hot-swapping of hard drives. Check Tierra Data Recovery for more information.
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