Lenovo ServeRAID M5120, User Manual

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1-6 Overview
each virtual disk. Table 1.1 shows the minimum number and the
maximum number of drives required for each RAID level.
1.5 Benefits of the SAS Interface
SAS is a serial, point-to-point, enterprise-level device interface that
leverages the proven SCSI protocol set. SAS combines the advantages
of SATA and SCSI, and is the future mainstay of the enterprise and high-
end workstation storage markets. SAS offers a higher bandwidth per pin
than parallel SCSI, and it improves signal and data integrity.
The SAS interface uses the proven SCSI command set to ensure reliable
data transfers, while providing the connectivity and flexibility of
point-to-point serial data transfers. The serial transmission of SCSI
commands eliminates clock-skew challenges. The SAS interface
provides improved performance, simplified cabling, smaller connectors,
lower pin count, and lower power requirements when compared to
parallel SCSI.
The ServeRAID-M5120 controller leverages a common electrical and
physical connection interface that is compatible with Serial ATA
technology. The SAS protocols and the SATA III protocols use a thin,
7-wire connector instead of the 68-wire SCSI cable or 26-wire ATA cable.
The SAS/SATA connector and cable are easier to manipulate, allow
connections to smaller devices, and do not inhibit airflow. The point-to-
Table 1.1 Physical Devices Required for Each RAID Level
RAID
Level
Minimum # of
Physical Devices
Maximum # of
Physical Devices
0 1 32
1 2 32
5 3 32
6 3 32
10 2 240
50 6 240
60 6 240