Adaptec's Series 5 Unified Serial Controllers Dissected

A RAID controller certainly isn’t a product that users buy at retail. Although almost all controller products are indeed available through e-tail and retail channels, more typical customers are system builders who require the controller to power their storage solutions. The new Adaptec Series 5 RAID controller family is designed to power workstations, servers with DAS storage, SAN appliances, NAS storage and other related solutions, which are crucial for small, medium and large businesses. We wanted to know how the new combined SAS/SATA cards compare to the established competition, and that’s what we’re going to find out.

Storage controller cards were once an essential component of PCs, providing the basic connectivity for drives that is now built into chipsets. No longer needed in that market, storage add-on cards have now moved into business segments with specific applications. Servers and workstation systems typically require sophisticated RAID controllers; high-end desktops or enthusiast systems don’t. But the current generation of RAID controller cards is not only powerful and extremely flexible, but also amazingly scalable - they can be used with low-cost SATA or high-end SAS hard drives, hooking up drives internally or externally.

Before the introduction of SAS (Serial Attached SCSI), a controller’s market positioning was defined purely by its interface: UltraATA or SATA controllers were entry-level hardware for SMBs, while SCSI products catered to enterprise applications due to their more sophisticated features and flexible connectivity. Today, SAS controllers are referred to as Unified Serial controllers, which means that a SAS device can handle and even mix both SAS and SATA hard drives. Each SAS controller offers a certain number of ports, but SAS allows you to run four 300 MB/s SAS connections through a multi-lane cable for drives or expanders. SAS edge expanders enable administrators to connect additional drive appliances to create a so-called SAS domain. All drives in such a domain - which has similarities to Ethernet with its switches - are managed by the Unified Serial controller.

The Unified Serial controller market must be differentiated based on port count - since sophisticated models require tremendous internal bandwidth - as well as feature set. Unified Serial RAID can also be created by having the system processor take care of all processing workloads (host-based RAID), or by providing dedicated hardware acceleration (hardware RAID).

Adaptec’s new Series 5 PCI Express RAID controllers are based on a 1.2 GHz dual core storage processor, provide a very comprehensive feature set, and come in eight different flavours with four to 28 ports in internal and/or external port configurations. Let’s look at them in detail.

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