5486IOA.fm Draft Document for Review October 18, 2004378 IBM Eserver i5 and iSeries System HandbookThe #2782 is withdrawn from marketing in October 2004. The #2787 PCI-XFibre Channel Disk Controller is the recommended replacement.#2782 PCI-X RAID Disk Unit ControllerThe #2782 PCI-X RAID Disk Unit Controller is an Ultra SCSI disk unit controllerwith a 40 MB cache that provides RAID-5 protection for internal disk units. It alsosupports internal tape devices, CD-ROM, and DVD units. The #2782 has twoUltra SCSI buses.The #2782 is designed to work as a high performance controller for disksprotected by system mirroring or disks with no protection. In the RAID-5configuration, disk unit protection is provided at less cost than mirroring, and withgreater performance than system checksums.The #2782 controller supports a maximum of 12 disk units. DASD compressionis not supported.The #2782 controls up to two removable media devices (internal tape, CD-ROMand DVD).A minimum of three disk units of the same capacity are needed for a validRAID-5 configuration. A maximum of four arrays are allowed per controller, with amaximum of 12 disk units allowed per array.Parity is spread across either two, four, eight, or 16 disk units in an array, asrepresented in the following table.Important: A #2766 PCI Fibre Channel Disk Controller, supported on theiSeries with OS/400 V5R1, can be used to attach the IBM TotalStorageEnterprise Storage Server (ESS). The #2766 is not supported as a loadsource IOP in secondary (system is unable to IPL via a #2766), but remoteload source mirroring is supported through the #2766.Note: Due to a system unit and external tower disk cage designs, only theModels 270 and 810, and the #0595/#5095 PCI-X Expansion Tower have asuitable system configuration to allow 12 disk units to attach to a single #2782.All other system unit and tower disk configurations restrict the number ofattaching disk units to 10 or less.
