Xserve RAID is a mass-storage device that was offered by Apple Inc. Xserve RAID held up to 14 hot-swappable Ultra-ATA hard drives, and had a capacity of 10.5 TB when filled with 750 GB modules. Xserve RAID supported RAID levels of 0, 0+1, 1, 3 and 5 in hardware, hybrid RAID levels such as 10 and 50 could be created in software. It was rack-mountable and was 3U high.
Although the Xserve RAID contained 14 drives, they were split into two independent groups of 7 drives each managed by an identical RAID controller. Importantly, the controllers were independent, but not redundant; each managed seven of the storage array's fourteen drives, given a failure of one of the controllers those 7 drives were not accessible: the other could not take over its duties. Xserve RAID did, however, have redundant cooling units and power supplies. Xserve RAID's ports were two Fiber Channel ports for regular data transfer, a 10/100Ethernet port for remote management, and a serial port for UPS communication via the Simple Signaling Protocol.