If required, use a small screwdriver or the tip of a pen to push the small buttons
above and below each enclosure ID digit to change the enclosure ID setting. Press
the button located above the digit to lower the digit by one. Press the button located
below the digit to raise the digit by one.
Note:
Some DS4000 storage expansion enclosures ship with a panel installed over
the enclosure ID switch to prevent the enclosure ID from being changed
accidentally. If your DS4000 storage expansion enclosure has a protective
panel over the ID switch, use a pencil or a small screwdriver to change the
enclosure ID.
Each storage expansion enclosure in a DS4000 Storage Subsystem drive loop must
have a unique enclosure ID. DS4000 controllers use a combination of the enclosure
ID and the number of the physical slot that a hard drive occupies to create a unique
fibre channel loop address or arbitrated loop physical address (AL_PA) for each
drive in a fibre channel drive loop. The enclosure ID consists of two digits, a tens
digit (x10) and ones digit (x1).
Attention:
When connecting storage expansion enclosures, you must use the
tens digit (x10) enclosure ID setting to distinguish different redundant drive channel
pairs and use the ones digit (x1) enclosure ID setting to distinguish storage
expansion enclosures IDs within a redundant drive channel pair. For example, in a
DS4700 Express configuration with six EXP710 or EXP100 storage expansion
enclosures connected in a redundant drive channel/loop pair, the recommended
enclosure ID settings for the enclosures are shown in Table 30. EXP810 storage
expansion enclosures automatically set their enclosure IDs to be unique in a drive
channel pair.
Table 30. Recommended enclosure ID settings scheme when connecting a DS4700 to
EXP710s or EXP100s
Enclosure ID of storage expansion enclosures in a
redundant drive channel
Enclosure 1
11
Enclosure 2
12
Enclosure 3
13
Enclosure 4
14
Enclosure 5
15
Enclosure 6
16
The DS4700 Express normally ships with an enclosure ID outside the range of
00–77. However, if your DS4700 Express enclosure ID was set to a value within the
range of 00–77, it may be in conflict with the enclosure ID of one of the drive
expansion enclosures that you are trying to attach to the DS4700 Express. If this is
the case, the amber ID Conflict LED on the storage expansion enclosure will light
after you power on the storage subsystem.
Give each storage expansion enclosure in a redundant drive channel pair a unique
ones digit (x1) ID. This setting will enforce hard AL_PAs (unchangeable between
fibre channel Loop Initializations [LIPs]) for the drives and facilitate drive loop
problem troubleshooting in the event of an error. If the one's digits are not unique,
two or more devices will have the same hard AL_PA. In such a case, the DS4700
Express controller will use soft AL_PAs for the devices that have identical hard
AL_PAs.
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IBM System Storage DS4700 Express Storage Subsystem: Installation, User’s and Maintenance Guide
Summary of Contents for DS4700 EXPRESS
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