Das And San Storage Architectures - Sun Microsystems StorEdge3000 Series Manual

All six fibre channels in an I/O controller module support 1-Gbit or 2-Gbit data
transfer speeds.
RAID controller channels 2 and 3 are dedicated drive channels that connect to
expansion units. Each I/O board has two ports designated as disk drive loops. These
ports connect to the internal dual-ported FC disk drives and are used to add
expansion units to the configuration. The two drive loop ports on the upper I/O
board form FC loop 2 (channel 2) while the two drive ports on the lower I/O board
form FC loop 3 (channel 3). FC loop 2 provides a data path from both RAID
controllers to the A loop of the internal disk drives, while FC loop 3 provides a data
path from both RAID controllers to the B loop of the internal disk drives.
Sun StorEdge 3511 SATA Array. RAID controller channels 0 and 1 are dedicated
host channels. Channels 4 and 5 are normally designated host channels but can be
configured as drive channels. RAID controller channels 2 and 3 are dedicated drive
channels that connect to expansion units.
How the channels are exposed on the StorEdge 3511 RAID controller is one of the
key differences between the StorEdge 3510 and 3511. Host channels 0 and 1 include
four ports per loop (two ports on the upper controller, and two ports on the lower
controller). Channels 0 and 1 support 1 Gbit or 2 Gbit data transfer speed.
Channels 4 and 5 provide two ports per loop (one port on each controller). Channels
4 and 5 only support 2 Gbit data transfer speed.
Each RAID controller has two ports designated as disk drive loops. The drive ports
support only 2 Gbit data transfer speed. These ports connect to the internal Serial
ATA disk drives using internal FC-SATA routing technology. Drive ports are used to
add expansion chassis to the configuration. Like the host channels, each drive
channel of the top RAID controller shares a loop with the matching drive channel on
the bottom RAID controller. For example, drive channel 2 of the top RAID controller
shares the same loop as channel 2 of the bottom RAID controller.

DAS and SAN Storage Architectures

There are two popular methods for connecting storage to servers.
Direct attached storage (DAS) uses a direct connection between a server and its
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storage system. The DAS solution of connecting each server to its own dedicated
storage system is straight-forward, and the absence of storage switches can
minimize costs in some instances.
A storage area network (SAN) places a Fibre Channel (FC) storage switch
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between network servers and storage systems. A SAN solution shares a storage
system among multiple servers using FC storage switches, and reduces the total
number of storage systems required for a particular environment at the cost of
additional element management (FC switches) and FC path complexity.
Best Practices for the Sun StorEdge 3510 and 3511 FC Arrays 5