IBM DS3950, Инструкция по установке, использованию и обслуживанию, Страница: 36 / 252

FC-SAS E-DDM FRUs have a FC-SAS interposer card that convert the 6 Gbps the
SAS protocol to a 4 Gbps FC interface protocol. Operate these FC-SAS and SATA
E-DDMs at 4 Gbps Fibre Channel operating speed.
Note: Even though the DS3950 has a 2 or 4 Gbps Fibre Channel Link Rate switch
that can be used to set the drive channel speed at 2 Gbps, the link rate
speed must be set to 4 Gbps. The DS3950 supports only 4 Gbps FC speed in
the drive channel. See “Verifying the link rate setting” on page 138 for more
information.
Important: Do not change the speed of a drive loop while the storage subsystem is
powered on. Such a speed change will cause unpredictable results.
Also, the drive expansion enclosures must be power cycled for the new
speed setting to be correctly recognized.
If you need to change the speed of a drive loop, complete the following steps:
1. Prepare applications for storage system shutdown.
2. Shut down the storage system.
3. Shut down the storage expansion enclosures.
4. Change the storage expansion enclosure speed settings.
5. Power on the storage expansion enclosures.
6. Power on the storage subsystem.
7. Restore storage subsystem host application operations.
The Link Rate switch on the DS3950 storage subsystem and the storage expansion
enclosures connected to it must have the same setting.
The DS3950 drive tray is not interchangeable with the drive tray of other DS4000
storage subsystems such as DS4100 or DS4300 storage subsystems. The DS3950
E-DDM option CRUs are not interchangeable with those of the DS4200 Express
and EXP420. When replacing an E-DDM CRU, be sure to order and install the
correct E-DDM CRU. Using non-supported E-DDM options or FRUs will result in
the E-DDM being locked out by the DS3950 controller firmware and might also
damage the drive connector in the enclosure midplane.
Attention:
1.
After you remove an E-DDM CRU, wait 70 seconds before replacing or
reseating the E-DDM CRU to allow it to properly spin down. Failure to do so
might cause undesired events.
2. Never hot-swap an E-DDM CRU when its associated green Activity LED is
flashing. Hot-swap an E-DDM CRU only when its associated amber Fault LED
lights is not flashing or when the E-DDM is inactive and its associated green
Activity LED lights is not flashing.
Note: If the E-DDM you want to remove is not in a failed or bypass state, always
use the Storage Manager client program either to place it in a failed state or
to place the array that is associated with the E-DDM (or E-DDMs) in an
offline state before you remove it from the enclosure.
Controllers
The DS3950 has two hot-swappable and redundant RAID controllers. The
controllers are located at the back of the storage subsystem. The left controller is
labeled controller A, and the right controller is labeled controller B. One controller
will continue to operate if the other controller fails.
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IBM System Storage DS3950 Storage Subsystem: Installation, User’s, and Maintenance Guide