Advantech ASR-5300I Series, Руководство пользователя

Страница: 67 / 122

57 ASR-5300I Series Hardware User Manual
Chapter 3
S
ystem
Connection
Fault-Tolerant Links to SAS Disk Drives
 SAS expansion cables are provided with the JBODs. If numerous JBODs are
connected, a longer SAS external cable (e.g., 120 cm) may be necessary for
connecting a JBOD from the opposite direction to offer high redundancy.
 One expansion link connects JBODs from RAID to the nearest JBOD, and then
to the farthest JBOD. Another expansion link connects to the farthest JBOD
from the opposite direction and then to the nearest JBOD.
 Each expander controller on the SAS JBOD controls an SAS domain that
connects one of the alternative interfaces on every disk drive in the enclosure.
For example, one expander unit controls Domain A, and the other controls
Domain B. In a fault-tolerant topology, the SAS external links always connect to
the SAS ports on the same SAS domain.
 The SAS domains can be identified by the expander location, for example, the
upper controller slot (Controller A/Slot A) or lower controller slot (Controller B/
Slot B).
 On the RAID system, each RAID controller can be considered as managing a
separate SAS domain. Using the port selector mechanism on the MUX boards,
the concept of a SAS domain applies even when SATA drives are used in a
dual-controller JBOD.
3.7.4 Dual-Controller Expansion Connection
 RAID system top SAS exp. -> 1st JBOD top SAS-IN

1st JBOD top SAS-OUT -> 2nd JBOD top SAS-IN
 1st JBOD bottom SAS-IN port –> 2nd JBOD bottom SAS-OUT
 RAID system bottom SAS exp. –> last JBOD bottom SAS-IN