IBM System Storage DS4000, Hardware Maintenance Manual

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Table 32. DS4300 storage server fan LED
LED Color Operating states
1
Fault Amber
v Off - Normal operation
v On - The fan FRU failed.
1
Always use the storage management software to identify the failure.
Table 33. DS4300 storage server power supply LEDs
LED Color Operating states
1
Fault Amber
v Off - Normal operation
v On - One of the following situations has occurred:
– The power supply failed.
– An overtemperature condition has occurred.
– The power supply is turned off.
Power Green
v On - Normal operation
v
Off - One of the following situations has occurred:
– The power supply is disconnected.
– The power supply is seated incorrectly.
– The storage server has no power.
1
Always use the storage management software to identify the failure.
Cache memory and RAID controller battery
Each RAID controller contains 128 MB of cache data. It also contains a rechargeable
battery that maintains data in the cache in the event of a power failure. The
following sections describe these features and their associated LEDs.
Cache memory
Cache memory is memory on the RAID controller that is used for intermediate
storage of read and write data. Using cache memory can increase system
performance. The data for a read operation from the host might be in the cache
memory from a previous operation (thus eliminating the need to access the drive
itself), and a write operation is completed when it is written to the cache, rather
than to the drives.
Power supply
fault LEDs
Power LED
Fan fault LED
Fan fault LED
Power LED
Figure 52. DS4300 storage server fan and power supply LEDs
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IBM TotalStorage DS4000: Hardware Maintenance Manual