Fantec SQ-X2RU3e Manual - Page 12

RAID 1 (Mirroring): The RAID1 storage policy stores all data in duplicate on separate drives to protect against data loss due to drive failure. One drive mirrors the other at all times. Every write operation goes to both drives. RAID1 provides the highest level of data protection for critical data that you cannot afford to lose if a hard drive fails, but halves the amount of storage capacity because all data must be stored twice. The resulting storage capacity of the virtual RAID1 volume will be equivalent to the size of one hard drive (if both drives are the same) or the smaller of the two drives (if they are different). If one drive fails, the RAID1 volume is still usable, but it is in a vulnerable state because its mirrored hard drive is inaccessible. When the offline drive comes back online, the appliance begins a rebuild process immediately to restore data redundancy. Although the volume remains available during the rebuild process, the volume is susceptible to data loss through damage to the remaining drive until redundancy is restored at the end of the rebuild and verification process. Host access takes precedence over the rebuild process. If you continue to use the SAFE volume during the rebuild, the rebuild process will take a longer time to complete, and the host data transfer performance will also be affected. RAID1 250GB FANTEC SQ-X2RU3e Port 0 Port 1 Drive A 250GB Drive B 250GB Equal hard drives RAID1 250GB FANTEC SQ-X2RU3e Port 0 Port 1 Drive A 250GB Drive B 750GB Unequal hard drives 11