User`s guide

3
StorageWorks Replacement Procedures
This chapter describes the detailed procedures for replacing SBB and blowers and
the general procedures for replacing shelves. These procedures are applicable
to all StorageWorks shelves except as noted. The procedures for replacing
controllers and cache memories are described in the individual shelf manuals.
The most critical factors relating to removing or replacing storage SBBs or
expanding a StorageWorks system are as follows:
• The device type
• The SCSI bus
• The SCSI bus device address
Once a device has been initialized on a SCSI bus with a specific device address,
moving the device to another bus or changing the device address can cause
problems on the bus. Therefore, it is imperative that devices remain on the same
bus and use the same device address. Be sure to clearly identify the bus and
device address for each storage device before removing them.
When adding devices to a random array of independent disks (RAID) set it
can involve adding shelves and rerouting the SCSI buses. Rerouting a SCSI bus
to a different shelf requires that the configured SBBs must be located in the same
logical location, that is the same bus and and the same device address, that they
were prior to the expansion.
3.1 Replacing a Storage Device or a Power Unit
There are three methods for replacing SBBs, including power supplies—the
hot-swap method, the warm-swap method, and the cold-swap method. You
must determine the appropriate replacement method prior to replacing a device
or power supply.
The LEDs on the front of the SBB indicate the status, either operational or
non-operational.
• For storage SBBs, you can use the hot-swap method providing that device is
not active (that is, the green device activity LED is off).
CAUTION
A hot-swap is a method of device removal that allows SBB removal and
replacement while the rest of the system remains on line and active.
Not all controllers support the hot-swap method. Read the controller
documentation to determine which controller-supported swap method may
be used.
StorageWorks Replacement Procedures 3–1