Adaptec Serial Attached SCSI End User Manual page 4

Putting Serial Attached SCSI to Work for You
TAPE LIBRARY DISK STORAGE
SERVER WITH
BACKUP SOFTWARE
LAN
One Common Disk-to-Disk-to-Tape
Solution
Economics of Serial Attached SCSI
SAS provides SCSI-like price, performance, and reliability points between Fibre Channel
and SATA to give you more flexibility in choosing solutions. Table 1 illustrates the cost
differentials between these three technologies on an identical disk-to-disk-to-tape
configuration. An approximation of a sample configuration is used in the example in
Table 1 to illustrate the cost/performance benefits of SAS in this solution. Keep in mind
that a SAS drive can read and write at least twice as fast as SATA.
Fibre Channel
Tape Library
Drives
Media
1U Server
Cabling & Controller
Backup Software
Accessory Cost:
Disk Array
RAID Controller Dual Redundant
Disk Drives (3TB)
Enclosure/Drive
Disk Storage Cost:
Table 1. .Sample configuration pricing based on March '05 pricing from several major catalog reseller websites. Items priced were 3TB Adaptec storage
enclosures, HP Windows-based servers, VERITAS Backup Exec with library support, and a 3TB Quantum M1500 library.
Remember that the actual cost of any of these technologies is more than the cost of
acquisition, and you need to look at the Total Cost of Ownership (TCO) or what you will
need to invest in deployment, maintenance, and administration costs. Take Fibre
Channel, which has a high acquisition cost and a high TCO, for example. This combined
cost means that Fibre Channel deployments usually are found in SANs, and that you are
investing heavily in a dedicated high-speed network to enhance storage reliability and
performance, including more efficient movement of information over multiple locations.
The implied TCO costs usually include dedicated storage IT staff that requires extensive
FC and SAN training, the expense of multiple software technologies being utilized to
track and manage the effectiveness of SAN data movement, the cost of the cabling
infrastructure, and depending on replication and remote location integration, the ability
to replicate data over a carrier's long distance fibre network. This means that acquisition
and TCO costs are high for a SAN, which has limited its wide market adoption into
mainstream datacenters around the world.
Similarly, SATA configurations offer performance trade-offs. Though SATA provides the
lowest initial acquisition cost, it does not offer mainstream enterprise feature
functionality. SAS, however, delivers a compelling value proposition for the mainstream
IT datacenter — the benefits of lower costs, high performance, and flexible hardware
configurations, improved margins and customer satisfaction on nearly any storage
solution. Keep in mind also that if you are using SAS, you can continue to use that
enclosure for a different purpose as storage needs change over time, creating a compelling
TCO value proposition.
Mix and Match Architectures for Flexible Cost Structures
The value and flexibility of SAS enables a variety of new storage solutions that haven't
been possible before:
• Highly reliable, high-performance primary storage for small and medium businesses
who can't afford a Fibre Channel solution.
Serial Attached SCSI
~$20,000 ~$20,000
2 2
SDLT 320 SDLT 320
~$4000 ~$4000
~$500 ~$500
~$1000 ~$1000
~$25,500 ~$25,500
Dual Redundant
10x300GB 10x300
FC/FC FC/SAS or SATA
~$40,000 ~$20,000
S A S E N D - U S E R G U I D E
4
Serial ATA
~$20,000
2
SDLT 320
~$4000
~$500
~$1000
~$25,500
Dual Redundant
12x250GB
FC/SATA
~$18,000