Hitachi CBL, Hardware Service Manual

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9–2
Replacing cache memory
Hitachi Unified Storage Hardware Service Guide
Precautions when replacing cache memory
Observe the following guidelines when replacing cache memory.
• The CBXSS/CBXSL/CBXX/CBSL and CBL use different cache memory
modules. When replacing cache memory, be sure to use the
appropriate module for the Hitachi Unified Storage system.
• Insert the new cache memory in the slot number appropriate for the
cache memory being replaced.
• Complete the cache replacement within 10 minutes. Otherwise, an
abnormal rise in temperature can power off the storage system.
• To replace cache memory, you must remove the controller where the
faulty cache memory is installed. Before removing the controller, bock it
to place it out of service.
• When replacing cache memory, the new cache memory must be the
same capacity as the cache memory being replaced.
• If you replace a controller while the storage system is formatting a
volume, the time it takes to restore the new controller might be
delayed until the volume-formatting operation completes.
• To replace cache, you must remove the storage system controller. For
storage systems that have the Power Saving/Power Saving Plus option,
removing and inserting a controller during drive spin-up might prevent
the controller from recovering fully. If this occurs, wait for all the drives
to spin up, and then remove the controller from the storage system,
wait at least 30 seconds, and reinsert it.
Replacing cache on CBXSS/CBXSL/CBSS/CBSL Controller
Boxes
To replace cache on CBXSS/CBXSL/CBSS/CBSL Controller Boxes:
1. Be sure the red ALM LED is ON at the controller whose cache memory
you want to replace. If it is not ON, visit the HDS Support Portal at
portal.hds.com .
2. Loosen the right and left blue screws.
3. Open the right and left levers forward.
4. Remove all the cables connected to the controller. If the Drive Box is
connected, remove the SAS (ENC) cable.
NOTE: You cannot replace two cache backup batteries on the CBSL/CBSS/
CBXSL/CBXSS at the same time when the storage system is powered on
(Ready status). You can replace two cache backup batteries on the CBL
while the storage system is operating; however, the cache switches to
write-through mode and read/write performance degrades slightly.