S A S
E N D - U S E R G U I D E
3
Putting Serial Attached SCSI to Work for You
can redeploy a new SCSI-based solution before the weekend is through. This does not
account for the vendor negotiation of taking back the ‘slightly used’ SATA solution, and
replacing it with a SCSI solution.
SAS breaks these barriers. Deploying standard server and storage chassis based on SAS
architecture makes it easy to purchase and maintain service spares by leveraging common
components (power supplies, memory, etc.), and ensures that IT staff is up to speed and
very comfortable with the server and storage solution.
The most compelling part of SAS is that the datacenter manager can now customize the
type of storage for an environmental infrastructure. If the application is not mission
critical or consumes capacity at an unmanageable pace, SATA hard drives can be
deployed into the SAS ecosystem, which is able to auto-negotiate with both SATA and
SAS hard drives. If needs change and performance and reliability become the dominant
requirement, the IT manager can simply migrate existing SATA hard drives to more
robust SAS hard drives, then redeploy the SATA technology into another server or storage
farm. All this can be done without having to forklift upgrade or disrupt the application
server or storage chassis.
Serial Attached SCSI Market Overview
Today, in the $13 billion storage marketplace, three dominant technologies account for
the lion’s share of sales: SCSI, Fibre Channel, and SATA.
As shown in
Figure 1
, current technology requires the use of different hard disk types to
meet the needs of the common range of applications. Each hard disk type must use a
controller with the same interface type. For example, a high-end performance system
based on Fibre Channel disk drives requires a Fibre Channel controller interface. Some
Fibre Channel deployments are Storage Area Networks (SANs) in which large data
centers have deployed a dedicated high speed network and require dual redundant paths
right to the hard drive to ensure reliability and performance.
An affordable low-end SATA storage solution requires both SATA hard disks and a
controller with a SATA interface. This inflexibility limits your choice in solutions and
forces tradeoffs in your storage, such as performance and cost.
In contrast, SAS will become a nearly universal interface, dramatically changing the
storage landscape and dominating market share and revenues. As shown in
Figure 2
, SAS
will give you new, more cost-effective performance options for the high-end applications
currently dominated by expensive Fibre Channel solutions. A SAS backplane also
supports SATA disk technology, allowing you more flexibility in the solutions you can fit
into one common storage enclosure. It also provides investment protection: start with
low-cost SATA drives, then migrate to SAS drives as needs change, for Fibre Channel-
comparable performance in the same enclosure. In fact, for many business solutions, SAS
allows you to more finely tune the relationship between performance and price point
while dramatically simplifying overall system management.
The transition from parallel SCSI and Fibre Channel technologies to SAS is starting right
now, with SAS being integrated into solutions that will be ramping in 2005. In fact,
SearchStorage has forecast that this year SAS will become the hottest direct attached
storage (DAS) connection technology. Quite simply, by the end of 2005, SAS will be the
industry’s fastest growing storage technology.
Fibre Channel
High-end
Mid-range
Low-end
SCSI
SATA
Disk Drive Type
Applications
Fibre Channel
High-end
Mid-range
Low-end
SCSI
SAS
SATA
Disk Drive Type
Applications
Storage Connectivity Market Today
SAS Impact on Storage Connectivity
Figure 1: Today, applications are
addressed by specific drive types.
Figure 2: SAS gives you new flexibility
to choose the drive performance
requirements needed at any point-in-
time at a price point that makes sense
for your budget.
