LaCie 2BIG NAS User Manual page 227

RAID 1
RAID 1 provides enhanced data security since all data is written to each disk in the volume. If a single disk fails,
data remains available on the other disk in the volume. However, due to the time it takes to write data twice,
performance is reduced when compared with RAID 0. Additionally, RAID 1 reduces the available disk space by
50% since each bit of data is stored on both disks in the volume.
Note on RAID 1 disk requirements: A standard RAID 1 configuration includes two disks of equal capacity.
When using disks of unequal capacities, the available storage space for data is that of the smaller disk.
It is possible to create a RAID 1 volume using a single disk. While such a volume cannot provide any data
protection, it is ready for expansion when you add a new disk. Data protection would become available once
the second disk is added to the RAID 1 volume.
LaCie 2big NAS | LaCie 5big NAS Pro User Manual 227