Sun Microsystems StorEdge D2, Installation, Operation And Service Manual

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1-12 Sun StorEdge D2 Array Installation, Operation, and Service Manual • February 2002
Depending on the array’s configuration, one or two ESMs monitor and report the
status of the disk drives.
FIGURE 1-6
Disks Controlled by a Single ESM and by Two ESMs
In a single-bus configuration, as indicated on the left in
FIGURE 1-6
, the single ESM
controls all disks. In a split-bus configuration, the array becomes two independent
storage subsystems. Each ESM monitors half the disks (all disks in the six drive slots
that are diagonally across from it).
Unit ID Ten-position switch for setting a unique ID for each ESM. When this switch is
used to set a unit ID, an application (such as Network Storage Agent) can use
SAF-TE commands to locate the ESM by its ID. See
FIGURE 1-9
for a close-up.
ESM Over
Temperature/Code
Download LED Yellow: Temperature exceeds the factory preset limits. When this LED is yellow,
the Subsystem LED also turns amber. (See “Array Front With Door Open and
Disk Slots Accessible” on page 1-7 for the location of the Subsystem LED.)
Blinking: A code download is in progress.
Off: Temperature is normal, and a code-download is not in progress.
Power ON/SCSI
Active LED Green: Power is applied.
Blinking: SCSI activity is occurring through the ESM.
Off: Controller is not receiving power.
TABLE 1-5
Connectors, Switches, and LEDs on the ESM
ESM 0 ESM 0 ESM 1
Front
Back
Single-bus configuration Split-bus configuration