LaCie 2BIG NAS User Manual page 267

RAID 5
RAID 5 writes data across all disks and a parity block for each data block is written on the same stripe (p in the
illustration below). A minimum of three disks is required to create a RAID 5 volume. If one physical disk fails, the
data from the failed disk can be rebuilt onto a replacement disk. No data is lost in the case of a single disk
failure, but if a second disk fails before data can be rebuilt to the replacement hard drive, all data in the array
will be lost.
LaCie 2big NAS | LaCie 5big NAS Pro User Manual 267