The high reliability storage array with a fully
Redundant Power System - RPS.
The Background: "The chain
is only as strong as its weakest link"
The disk drives available today have been designed for both
high reliability and high performance. Most new disk drives are
boasting MTBF ratings in excess of 500,000 hours or more than
57 years. Some are even rated at more than one million hours;
almost 115 years. But what good is the perfect disk drive if
its power supply fails? The average power supply today has an
MTBF of only about 25,000 hours or less than 3 years. Even the
most expensive power supplies used in the computer industry today
barely exceed 50,000 hours. While your disk drive is not likely
to fail over its useful life, its power supply very likely will.
To solve this problem, American Digital Systems developed MasterDisk®
RPS, the MasterDisk® Redundant Power System.
RPS utilizes an independent power
supply for each drive in the MasterDisk RPS chassis. The failure
of one power supply won't effect the rest of the drives in the
RPS storage array. But to further protect the storage system,
RPS incorporates an additional power supply; a hot spare; which
is online and ready to take over the responsibilities of any
other supply in the system should the need arise. RPS uses a
high speed switching circuit to immediately remove the defective
power supply from its target drive and replace it with the hot
spare power supply. The switching time is only 30 billionths
of a second and the drive never even knows that a power supply
had gone down. An integral microprocessor controlled circuit
monitors all power supplies in the array including the hot spare
supply and even keeps a history of their performance. When a
failure has occurred, the microprocessor sounds the audible warning,
flashes the supply failure light, displays a message for the
user showing which power supply has failed and exactly how it
has failed and even marks the defective power supply.
And if the RPS chassis is in the computer room and you're
not, a remote alarm can be wired to the operator's console or
a digital pager. All you have to do is go to the rear of the
chassis, pull the defective power supply out and replace it.
There is no need for tools; no need to turn off the AC power,
no need to halt the processor or reboot. In fact, if you replace
a defective power supply within one hour of the failure, the
MTBF of available power to the disk drives grows from 25,000
hours to more than 1,500,000 hours, more than 170 years.
The MasterDisk RPS chassis supports all standard SCSI busses
including SCSI 1, SCSI 2, Fast SCSI 2, Ultra SCSI and the new
Ultra 2 SCSI with differential, single ended or Low Voltage Differential
transmission. MasterDisk® RPS can be connected to any SCSI
based computer system and most systems which do not use a native
SCSI bus. The MasterDisk® RPS chassis can house up to 7 drives,
8 power supplies and a wide variety of performance enhancing
features including MasterCache, MasterDisk RAID controllers and
MasterDisk® RF-Series DSSI to SCSI protocol converters.
Drive types can include magnetic disk drives, 4mm tape and
rewritable optical disk drives. To make the system even easier
to use, the drives are mounted to removable modules which can
be quickly inserted or removed, even when the system is running
- inserted or removed without tools. We've even installed redundant
cooling fans and a sophisticated air flow monitoring system which
is monitored by the microprocessor.
RAID - For Even More Protection
The hot topic in disk storage
systems today is RAID, Redundant Array of Inexpensive Disks.
RAID protects your data by storing it across multiple disk drives.
Should one disk drive fail, the data can be either copied from
the mirrored disk or reconstructed from the remaining disks in
the array. It's a great concept and MasterDisk® RPS is ready.
The RPS chassis is has all of the necessary provisions for RAID.
And the combination of RPS and RAID gives your data the maximum
American Digital Systems is so sure of its quality, it backs
every MasterDisk® RPS storage system with a full five year
warranty. That's five years of peace of mind.
Drives per chassis
up to 7
magnetic disk, 4mm tape, rewritable optical disk
Drive form factor
3 ½" half height (1.6") or 1" thick
SCSI (SCSI 1), SCSI 2, Fast SCSI 2, Ultra SCSI, Ultra 2 SCSI
- can be intermixed, SCSI single ended, Low Voltage Differential
or differential - up to 7 independent SCSI buses per chassis
All SCSI based systems, servers and workstations and their operating
systems including all DEC Alpha, VAX and RISC, all Sun, all SGI,
all PC workstations and servers including Windows, NT and Unix,
Macintosh, HP, IBM RS6000
System is fully compatible with all currently available SCSI
RAID controllers and supports RAID levels 0, 1, 3, 5 and combinations
of those levels - space provided in chassis for RAID hardware
System provides space and support for additional internal modules
such as single-ended to differential converters, RAID controllers,
DSSI converters, MasterCache caching modules, etc.
Fully redundant DC power providing available power with an MTBF
of 1.6 million hours (> 182 years), one supply per drive plus
a redundant supply for the array - up to 8 power supplies per
chassis - power supply redundant switch over time < 30 nanoseconds
Drives mounted to removable modules at front of chassis for quick
replacement by unskilled personnel - MTTR less than 1 minute
Power supply mounting
Power supplies mounted to removable modules at rear of chassis
for quick replacement by unskilled personnel - MTTR less than
Microprocessor controlled system monitor for all supply voltages
within chassis and proper system cooling - LED display to show
system status and fault conditions - audible and visual warning
indicators - remote warning indicator
Rack mount - industry standard 19" equipment rack, 5¼"
high (3U), 25" deep
Table top mount - 19" wide x 5 ½" high x
Floor stand mount - 20 ½" high (including foot
assembly) x 25" deep x 5 ¼" wide (8 ½"
wide across foot assembly)
34 pounds (nominal) plus 2.1 pounds per drive (nominal) and 14
ounces per power supply
AC power requirements
90 to 264 VAC, 47 to 63 Hz, 25 Watts per drive typical, 63 Watts
per drive maximum
DC power source
+5 VDC ± 2% @ 4A maximum, +12 VDC ± 2% @ 3A maximum
per drive module
Redundant 5" dc fans with air flow monitoring circuitry
Controls and indicators
Chassis - LED display status panel, DC OK, Fault, Front Fan
failure, Rear Fan failure status lamps, audible warning with
acknowledge, remote warning circuit, AC power with indicator
Disk Drive Module - SCSI ID display, SCSI ID selection (0-9
and A-F), drive activity indicator, drive power safety switch
Power Supply Module - Module OK status lamp
SCSI or wide SCSI, up to seven busses per chassis, optional non-SCSI
busses such as DEC DSSI, remote warning connector
Temperature - 5° to 50° C operating
Temperature - -20° to 75° C storage
Altitude - -1,000 to 20,000 ft operating
Altitude - -1,500 to 60,000 ft transit
Humidity - 5% to 90% non-condensing operating
MTTR (mean time to repair)
Power supply module replacement - < 1 min
Drive module replacement - < 1 min