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Putting Serial Attached SCSI to Work for You
What is Serial Attached SCSI?
Finally, the most pervasive enterprise technology has come to a crossroads. Parallel SCSI
is the heart of the datacenter, used as the standard interconnect and hard drive
communication scheme for server and storage environments. Companies had been
developing and utilizing SCSI for over 20 years as the mainstay for enterprise storage.
But the technology’s future was coming into question. Quite simply, the parallel interface
would have to be overhauled to address next generation concerns of signal integrity,
performance and reliability, right down to fundamentals like cable length.
The result of three years of industry discussions and technological investigation is Serial
Attached SCSI (SAS), the next standard in enterprise server and storage technology. SAS
is a high-performance solution that leverages proven SCSI functionality, and builds on
the enterprise expertise of multiple chip, board, drive, subsystem, and server
manufacturers throughout the industry. It provides better performance and flexibility
than the serial technology, Fibre Channel, at a lower cost and with the same, or ever
better, reliability.
Key SAS Features Include:
• SAS and SATA drive support providing an unprecedented level of choice in the
enterprise — the flexibility of integrating either SAS and/or SATA devices in common
server or storage solutions, providing customization to meet cost or performance
needs in unique business environments
• reliable point-to-point connections at 3Gb/s — up to 128 devices (or 16,256
addressable devices per port)
• full dual-ported connections for performance or failover capabilities, delivering robust
data protection and reliability right to the hard drive
• enterprise features including native command queuing and greater than 2TB LUN
support
• available in multiple hot-swappable disk drive performance and form factor
configurations including high value 3.5” 10k rpm drives, high performance 3.5” 15k
rpm drives and emerging 2.5” high density drives for performance server and
specialized high-performance storage applications
• thinner cabling than SCSI and ATA which delivers new cooling metrics and more
efficient airflow — critical in a dense computing environment where low profile
servers are racked and stacked with multiple external storage chassis. Effective heat
management and cooling schemes remain a top priority for IT managers today
delivering enhanced uptime and reliability guarantees in application sensitive
environments.
SAS delivers the high performance, scalability, and reliability required for bandwidth-
hungry mainstream servers and enterprise storage. SAS lends itself to the high-frequency,
immediate random data access required for transactional data applications such as online
purchases and bank transactions and provides the performance and security required for
mission-critical applications which demand data redundancy.
Most importantly, IT managers today cannot risk deploying the wrong type of solution.
Today, server or storage solutions represent finite choices — you must choose early on
whether you want a SATA-optimized server or storage solution, or whether you will pay
more upfront for a parallel SCSI optimized server or storage solution. If you deploy the
low-cost SATA solution, but the performance and reliability metrics fail to meet internal
user expectations and uptime service guarantees, the choice is straightforward — pick a
weekend, forklift upgrade the application and storage infrastructure, and hope that you
SAS delivers the high
performance, scalability, and
reliability required for bandwidth-
hungry mainstream servers and
enterprise storage.
SAS lends itself to the high-
frequency, immediate random
data access required for
transactional data applications
such as online purchases and bank
transactions and provides the
performance and security required
for mission-critical applications
which demand data redundancy.
“Adaptec validates the vision
of the Serial Attached SCSI
standard – with its SCSI
technology leadership,
comprehensive understanding
of reseller and end-user
requirements, and a broad range
of products that can be mix-and-
matched into SAS-based solutions
that meet a new range of storage
performance and pricepoint
needs.”
Greg Schulz, Sr. Analyst,
The Evaluator Group
