Adaptec Glossary
Overview
Glossary of Terms
» What is Serial Attached SCSI (SAS)?
» What RAID Level is Right for me?
What is RAID?
RAID stands for Redundant Array of Independent Disks and is a method of treating several individual disk drives as one logical unit (RAID array or logical drive) to improve security, reliability, and read and write performance.
RAID protects data and improves system performance by copying or spreading the same data over multiple drives. Data can be mirrored (duplicated on multiple drives), or striped (spread over multiple disks), or both, depending on the RAID level. If one of the drives in a logical drive fails, the data that’s stored on it can be reconstructed on a replacement drive, keeping data safe and available for users. Eight RAID levels (0, 1, 1E, 5, 6, 10, 50, 60) provide varying levels of performance and reliability based on the number of disk drives in the array.
University Training - What is RAID? »
Learn more about Microsemi Adaptec® SAS/SATA RAID Adapters »
What is Serial Attached SCSI (SAS)?
Serial Attached SCSI (SAS) is an evolution of parallel SCSI to a point-to-point serial interface. SAS moves multiple bits of data one at a time and data can move in both directions simultaneously across a SAS connection or link.
SAS connects end devices (such as disk drives and disk drive enclosures) through direct-attach connections or through expander devices, and can support up to 128 disk drives per RAID adapter.
University Training - What is SAS? »
University Training - Introduction to Microsemi Adaptec® SAS RAID »
What are RAID Adapters?
A RAID adapter is a circuit board or expansion card that is installed in a PCI slot on the host system motherboard and then connected with compatible cables to storage devices that are either internal —hard disk drives (HDDs) and/or Solid State drives (SSDs)—or external—storage enclosures such as JBODs.
A RAID adapter sits in the center of the input/output (I/O) path, communicating data from the host system to the storage devices and vice versa, taking on the tasks of storing and retrieving data that are otherwise done by the host system’s microprocessor (CPU). It does not rely on the host system for resources, instead freeing up the CPU to run applications.
University Training - What is a RAID Adapter? »
University Training - Getting Started with your RAID Adapter (part 1) »
University Training - Getting Started with your RAID Adapter (part 2) »
University Training - Microsemi Adaptec® Series 8 »
Learn more about Microsemi Adaptec® SAS/SATA RAID Adapters »
What are Host Bus Adapters?
An HBA is a circuit board or expansion card that physically connects a host system, such as a server, to internal and/or external storage, such as hard disk drives (HDDs), Solid State drives (SSDs), and external storage enclosures. An HBA allows a host system and connected storage devices to communicate with each other.
University Training - What is a Host Bus Adapter? »
University Training - Microsemi Adaptec® HBA 1000 Series »
Learn more about Microsemi Adaptec® SAS/SATA Host Bus Adapters »
What is a SAS expander card?
A SAS expander card allows the user to connect more SAS & SATA devices such as hard disk drives and SSDs to a single controller because it enables you to fan-out from a single connection to multiple connections. The Microsemi Adaptec® SAS expander card features SAS and SATA edge buffering capabilities that enable it to increase total throughput to the controller even when using 6 Gbps SAS drives. This is achieved by bursting data at 12 Gbps when connected to 6 Gbps SAS or SATA devices when utilized in conjunction with a 12 Gbps capable adapter such as the Microsemi Adaptec® Series 8 SAS RAID or SAS HBAs.
Learn more about Microsemi Adaptec® SAS Expanders »
What RAID Level is Right for me?
When choosing the RAID level for a new array, there are a number of factors to take into consideration. For example, what are your performance needs, what are your capacity needs, and what is your budget?
Choosing the Right RAID Level Whitepaper »