IBM Midrange System DS4000 Series Hardware Manual page 28

– Less power consumption: Because there is no power for the motor required to spin up
the magnetic platters and to move the heads, the drive uses less energy than a
traditional hard disk drive. Each SSD uses about half of the power of a 15K RPM HDD.
The savings can be substantial if a few SSDs can replace many HDDs to deliver the
same performance. This is particularly true for applications that were forced, for
performance reasons, to use large quantities of HDDs to get as many spindles as they
can, though they were only using a small portion of the disk capacity. Besides power
consumption savings, the overall system will weigh much less because SSDs are
already much lighter than HDDs.
SDD is supported in an EXP5000 expansion unit behind a DS5100 or a DS5300 storage
server. At the time of writing, one SSD model with 73 GB of capacity is supported.
Full Disk Encryption Hard Disk Drives (FDE HDD)
FDE is a technology that performs encryption on the hard disk drive at the hardware level.
The Fibre Channel hard drive contains a custom chip or application specific integrated
circuit (ASIC) that is used to encrypt every bit of data as it is written and also decrypts data
as it is being read. ASIC requires a security key to allow encryption and decryption to
begin.
FDE disk drives encrypt all the data on the disk. The secured drive requires that a security
key be supplied before read or write operations can occur. The encryption and decryption
of data is processed entirely by the drive and is not apparent to the storage subsystem.
FDE HDDs are supported on DS5000 models (DS5020, DS5100, and DS5300).
The FDE HDDs that are currently supported include:
– 4 Gbps FC, 146.8 GB/15k rpm
– 4 Gbps FC, 300 GB/15k rpm
– 4 Gbps FC, 450 GB/15k rpm
– 4 Gbps FC, 600 GB/15k rpm
Fibre Channel Hard Disk Drives (FC HDD)
Fibre Channel is an industry-standard interface that supports very high data rates as well
as many more devices than traditional SCSI or ATA/IDE technologies. It is also a serial
interface, and uses a loop topology. FC HDDs feature a full-duplex dual-port active/active
4 Gbps Fibre Channel interface. The DS4000 and DS5000 series storage servers can
mount different types of FC HDDs in terms of size and revolutions per minute (RPM):
– 4 Gbps FC, 73.4 GB/15k rpm (only DS4000 models)
– 4 Gbps FC, 146.8 GB/15k rpm
– 4 Gbps FC, 300 GB/15k rpm
– 4 Gbps FC, 450 GB/15k rpm
– 4 Gbps FC, 600 GB/15k rpm
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IBM Midrange System Storage Hardware Guide