#2780 PCI-X Ultra4 RAID Disk Controller
The #2780 PCI-X Ultra4 RAID Disk Controller is an Ultra4 (u320) SCSI controller with a maximum compressed write cache
size of 757 MB and maximum compressed read cache of one GB. The #2780 provides RAID-5 protection for internal disks
and also supports internal tape units, CD-ROM, and DVD units. The #2780 has four Ultra4 SCSI buses. In addition to
providing RAID-5 protection for disks, the #2780 PCI-X Ultra4 RAID Disk Controller is designed to work as a high
performance controller for disks protected by system mirroring or disks with no protection.
The #2780 PCI-X Ultra4 RAID Disk 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 is 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 when starting arrays in iSeries Navigator. An optimization of Balance is used by default when starting arrays from
DST or SST options. If disk units are included into an existing array, the number of parity drives does not increase, so parity
can 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.
The #2780 controls up to two removable media devices (internal tape, CD-ROM, and DVD).
The #2780 does not support DASD compression.
The #2780 has a battery that provides concurrent maintenance and improved resiliency.
Requires one 3V long PCI slot.
Placement rules:
Not supported in Slot 1 of #5094 or #5294.
The #2780 is supported in the models 9408-M25, 9409-M50, and 9406-MMA with a RIO-2 loop.
Further restrictions apply when a MES Conversion #0299 to add an Auxiliary Write Cache is made. The card
providing the write cache attaches to a #2780 on one of the Ultra4 SCSI buses, thus reducing the available SCSI
busses to attach disk drives by one.
SCSI port 1 can support LVD or single-ended devices.
SCSI ports 0, 2 and 3 are LVD only.
Minimum operating system level: IBM i 5.4 with 5.4.5 machine code
The #2780 is supported in the models 9408-M25, 9409-M50, and 9406-MMA with a RIO-2 loop.
The #2780 is a Customer Install Feature.
Since July 2005, the #2780 can only be ordered if system has mirrored protection (#0040 prerequisite). Order #0299 MES
Conversion to improve cache data redundancy when system has RAID protection.
Notes:
The auxiliary write cache controller #5590 with 1.5 GB write cache can be used with the #2780.
There is no performance gain using the #5590.
New order alternatives to the #2780 include #5738, or #5777 PCI disk controller 2780 PCI-X Ultra4 RAID Disk Controller
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