Yesterday there was a great piece over at TechRepublic on the confusing intersection of SAS, SATA and iSCSI arrays. For anyone who has ever had a difficult time understanding and differentiating these technologies, this is a very valuable resource. Excerpts are cross-posted below.
SATA and SAS are storage interface and bus types designed to aid in the movement of data from one place to another. Think of SAS and SATA as different kinds of computer interfaces, such as PCI Express, but there are actually multiple components that make up the overall SAS architecture.
- Initiators. The initiator is the SAS controller to which SAS expanders or targets can be connected.
- Expanders. Expanders sit between initiators and targets, but can also connect to other expanders, as you can see in Figure A. Expanders are sort of like network switches in that they can direct traffic and they provide the ability to scale the SAS architecture beyond single port limits.
- Targets. A target is either a SAS drive or a SATA disk. SATA disks can be connected to SAS expanders and initiators, but do not perform quite as well as SAS disks.
Anticipation is building over the upcoming release of Intel’s new Xeon processor E5 family. Formally announced last November in 2011, Intel unveiled some impressive stats for the new E5 line: full integration support for the PCI Express 3.0 base (which is estimated to double interconnect bandwidth over the PCIe 2.0 specification), over twice the performance in raw floating point operations per second (FLOPS), and substantially greater real-HPC workloads compared to the Xeon 5600 series.
