IBM 2763 PCI RAID Disk Unit Controller

• SCSI RAID Controller

IBM 2763 is an Ultra2 SCSI controller with a 10MB write-cache that is designed to control Ultra, Fast Wide, and Fast Narrow SCSI disk and tape units that are installed in the base system unit and the #7102: System Expansion Unit. It provides RAID-5 protection for internal disk units, supporting a maximum of 12 disk units, and up to two internal tape or CD-ROM units. In addition to providing RAID-5 protection for disks, #2763 is also designed to work as a high-performance controller for disks protected by system mirroring or disks with no protection. In the RAID-5 configuration, disk unit protection is provided at less cost than mirroring, and with greater performance than system checksums. A minimum of four disk units of the same capacity are needed for a valid RAID 5 configuration. A maximum of three arrays are allowed per controller, with a maximum of 10 disk units allowed per one array. All disk units in an array must be of the same capacity. Parity is spread across four disk units for arrays of four to six disk units. Parity can be spread across either four or eight drives for arrays of eight to ten drives. For systems started with eight to ten drives in an array and are later upgraded to 8, 9, or 10 drives, the RAID function must be stopped and then re-started before parity will be spread across all eight drives. This feature supports Concurrent DASD Add/Maintenance. The following disks can be placed into RAID-5 arrays: #6813/#9313: 8.58GB Disk Unit, #6817/#8917: 8.58GB 10k rpm Disk Unit, #6818/#8918: 17.54GB 10k rpm Disk Unit, #6824/#8924: 17.54GB Disk Unit. The following tapes can be supported by the #2763: #6381: 2.5GB 1/4-Inch Cartridge Tape, #6382: 4.0GB 1/4-Inch Cartridge Tape, #6383: 16GB l/4-Inch Cartridge Tape, #6386: 25GB l/4-Inch Cartridge Tape.