(#2780) - PCI-X Ultra4 RAID Disk Ctrl
The IBM #2780 is an Ultra4 (u320) SCSI controller with a maximum compressed write cache of 757MB and a maximum compressed read cache size of 1GB, that provides RAID-5 protection for internal disks and also supports internal tape units, CD-ROM and DVD units. The #2780 has four Ultra4(U320) SCSI buses.
In addition to providing RAID-5 protection for disks, #2780 is also designed to work as a high performance controller for disks protected by system mirroring or disks with no protection.
This controller also uses a Cache Battery Pack with can be replaced concurrent with system operation.
The #2780 controller supports a maximum of 20 disk units.
A minimum of three disk units of the same capacity are needed for a valid RAID-5 configuration. A maximum of six arrays are allowed per controller, with a maximum of 18 disk units allowed per array. All disk units in an array must be of the same capacity.
Parity is spread across either two, four, eight, or 16 disk units in an array. If an array of three disk units is started, parity is spread across two disk units. If an array of four to seven disk units is started, parity is spread across four disk units. If an array of 8-15 disk units is started, parity is spread across eight disk units. If an array of 16-18 disk units is started, parity is spread across 16 disk units.
The number of arrays and size of each array can be influenced by specifying an optimization of either "Balance", "Performance", or " Capacity" in Operations Navigator when starting arrays. An optimization of "Balance" will be used by default when starting arrays from the green screens. If disk units are included into an existing array, the number of parity drives does not increase, so parity may be spread across less than the preferred number of disk units. In this case the RAID function must be stopped and then started in order to redistribute the parity.
Note that this controller does not support DASD compression.
- Attributes provided: SCSI Raid Controller
- Attributes required: One 3V long PCI slot
Option Part Numbers
- 39J0454
- 39J5057
- 39J5581
- 42R5124
- 42R6249
- 97P6094
Option Model Support
- 9405-2780
- 9406-2780
- 9407-2780
- 9411-2780
 Option Guide
 StorFacts Report
StorFacts Report
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