46
•
A longer cable is available for making expansion links with a Dual Controller
configuration. A longer cable is required if connections to JBODs are made from two
opposite directions. Routing through two different connections can avoid loss of data
links if one enclosure fails in between.
There is a rotary ID switch on every expansion enclosure that is
manually configured using a flat blade screwdriver.
Configuring enclosure IDs:
•
The configurable IDs for JBODs are from 1 to 15. Usually the numbering starts from
the one closest to the managing Unified Storage System.
•
Make sure a unique ID is configured on each JBOD so that the SAS WWN addresses
of disk drives can be properly assigned. Unified Storage System firmware
automatically manages these addresses.
Configuration Rules
How to connect SAS interfaces across Unified Storage and JBOD enclosures:
•
Fault-tolerant links in Dual
Controller combinations: Corresponding to SAS drives’
dual-ported
interface, two physical links are available from each disk drive, routed
across the backplane board, each through a SAS expander, and then interfaced
through a 4x wide external SAS port.
•
With data paths through separate SAS domains, access to disk drives can be
continued in the event of a cable link or SAS JBOD controller failure.
Designation
Description
Designation
Description
1
Controller A
5
Dual-ported SAS drives
2
Controller B
6
Expander
3
JBOD controller A
7
To another JBOD
4
JBOD controller B
•
Fault-tolerant Links to SAS disk Drives
•
SAS expansion cables will be available with the JBODs. Note that if many JBODs are
connected, a longer SAS external cable (e.g., a 120cm cable) may be necessary for
connecting a JBOD from the opposite direction offering high redundancy.
