Sas/Sata Technology - HP 273914-B21 - Smart Array 6404/256 RAID Controller Technology Brief

Figure 1. PCIe data transfer rates
Lane 1 Send Lane 1 Send
Lane 1 Receive Lane 1 Receive
Source Source
n n
Lane Lane Send Send
n n
Lane Lane Receive Receive
NOTE:
10 bits of signaling are required to transport one Byte of data. Consequently in Figure
1, 5 Gb/s is shown as 500MB/s.
PCIe 2.0 is completely backward compatible with PCIe 1.0. A PCIe 2.0 device can be used in a PCIe
1.0 slot and a PCIe 1.0 device can be used in a PCIe 2.0 slot. Table 2 shows the level of
interoperability between PCIe cards and PCIe slots.
Table 1. PCIe device interoperability
PCIe x4 Connector
device type x4 Link
x4 card x4 operation
x8 card Not allowed
x16 card Not allowed

SAS/SATA technology

The newest serial, PCIe 2.0 capable Smart Array controllers use Serial Attached SCSI (SAS)
technology, a point-to-point architecture in which each device connects directly to a SAS port rather
than sharing a common bus as with parallel SCSI devices. Point-to-point links increase data
throughput and improve the ability to locate and fix disk failures. More importantly, SAS architecture
solves the parallel SCSI problems of clock skew and signal degradation at higher signaling rates.
The same Smart Array controllers are compatible with Serial Advanced Technology Attachment
(SATA) technology and include the following features to enhance performance and maintain data
availability and reliability:
• SAS and SATA compatibility — The ability to use either SAS or SATA disk drives lets administrators
deploy drive technology that fits each computing environment. HP Smart Array controllers can
manage both SAS arrays and SATA arrays. Smart Array configuration utilities help administrators
configure arrays correctly so that data remains available and reliable.
1 For more information about SAS technology, refer to the HP technology brief titled "Serial Attached SCSI storage technology"
available at http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01613420/c01613420.pdf .
Max. bandwidth
(Send or receive)
Link
size
PCIe 1.0
x1 250 MB/s
Target Target
x4 1 GB/s
x8 2 GB/s
x16 4 GB/s
x8 Connector x8 Connector
x4 Link x8 Link
x4 operation x4 operation
x4 operation x8 operation
Not allowed Not allowed
Total
(Send and receive)
PCIe 2.0 PCIe 1.0
500 MB/s 500 MB/s
2 GB/s 2 GB/s
4 GB/s 4 GB/s
8 GB/s 8 GB/s
x16 Connector x16 Connector
x8 Link x16 Link
x4 operation x4 operation
x8 operation x8 operation
x8 operation x16 operation
PCIe 2.0
1 GB/s
4 GB/s
8 GB/s
16 GB/s
1
5