New SAS 2.0 Features: Cabling, Connectors, And Value
10 Meter Cable Length
MiniSAS 4X Connectors
The days of the InfiniBand connector are numbered with SAS 6 Gb/s.
SAS 6 Gb/s requires mini-SAS, also known as iPass, connectors. Mini-SAS also works on 3 Gb/s links and is already available on many storage solutions.
Spread Spectrum Clocking
Varying clock speeds help to reduce electrical emissions so SAS can stay within FCC limits. If a wider range of frequencies is used, the peak amplitude of radiated emissions drops. This approach is required for 6 Gb/s SAS but not for the 3 Gb/s generation.
Value Proposition
This chart differentiates popular storage architectures for business and enterprise applications:
| Header Cell - Column 0 | Performance | Low Cost | High Distance |
|---|---|---|---|
| 4 Gb and 8 Gb Fibre Channel | Yes | - | - |
| iSCSI over Gigabit Ethernet | - | Yes | Yes |
| iSCSI over 10 Gigabit Ethernet | Yes | - | Yes |
| SAS 1.1 and 2.0 (3 and 6 Gb/s) | Yes | Yes | - |
Source: SCSI-TA.
The SCSI Trade Association positions SAS to coexist with Fibre Channel and iSCSI, but SAS clearly excels for value-oriented external solutions.