Most RAID modes use equal disk capacities among the pool of hard drives to protect data. Rather then lose storage capacity overhead in mixed disk environments, SimplyRAID preserves the extra space for use when new disks are added to the enclosure. This means that, unlike standard RAID models, you can easily expand the array without losing data. For example, two 1TB disks will create a RAID 1 array without any disk capacity overhead. However, one 1TB disk paired with one 2TB disk can only create 1TB of protection since data cannot surpass the storage capacity of the smallest disk. SimplyRAID will calculate the overhead and prepare it for future disk expansion.

Disks in a JBOD configuration store data sequentially. For example, data is written to Disk 1 first. Once Disk 1 is full, data will be written to Disk 2, then Disk 3, etc. Two advantages to this level of RAID are the availability of 100% of the disks' total storage capacity and easy expansion. However, all data will be lost if a single disk fails.

RAID 0 is the fastest RAID mode since it writes data across all of the volume's disks. Further, the capacities of each disk are added together for optimal data storage. However, RAID 0 lacks a very important feature for a NAS: data protection. If one disk fails, all data becomes inaccessible. When weighing performance against protection, keep in mind that a NAS's transfer rates are contingent upon the bandwidth of the network as well as its own hardware. For example, with both LAN ports bonded and connected to a router that supports port aggregation, the 5big NAS Pro cannot exceed 200MB/s. A recommended option is RAID 5, which offers comparable performance, approximately 75% storage capacity (based upon total available disks and storage capacities), and data protection.

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 multiple times, performance is reduced. Additionally, RAID 1 will cut disk capacity by 50% or more since each bit of data is stored on all disks in the volume.

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.

RAID 6 writes data across all disks and two parity blocks for each data block are written on the same stripe (p and q in the illustration below). A minimum of four disks is required to create a RAID 6 volume. If one physical disk fails, the data from the failed disk can be rebuilt onto a replacement disk. This RAID mode can support up to two disk failures with no data loss. RAID 6 synchronizing from a failed disk is slower than RAID 5 due to the use of double parity. However, it is far less critical due to double-disk security.

In a RAID 1 configuration, the same data is written across all hard disks in the volume, protecting your data against the loss of one disk. With RAID 5 and RAID 6, data is available from the parity blocks and protected should one or two drives fail, respectively. A RAID+Spare volume gives you a “hot-spare” that is ready to synchronize data immediately should a disk fail. If a hard disk in the volume fails, the data starts to synchronize with the spare. The clear advantage for a RAID volume with a spare is that you do not have to wait for a replacement disk.

When the failed disk is replaced, the replacement disk becomes the new hot spare.

To create a volume with a spare hard drive, you must choose Custom in the New volume wizard. Selecting Quick setup in the New volume wizard will automatically configure a volume with LaCie SimplyRAID and single disk protection. SimplyRAID optimizes disk space across all hard drives to maximize data storage. Therefore, it does not include the option to add a spare drive. See New Storage Volume Wizard for instructions on creating volumes with the New volume wizard.