install–38 - Ibm

Table 12. Fan LED
LED Color Operating states 1
Fault Amber v Off - Normal operation.
v On - The fan CRU has failed.
1 Always use the storage-management software to identify the failure.
Table 13. 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 has failed.
– An over-temperature condition has occurred.
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.
– The power supply is turned off.
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.
See the storage-management software documentation for information on setting
cache memory options.
The RAID controller has a Cache active LED that displays the current status of the
cache. The LED is on if there is data in the cache, and it is off if there is no data in
the cache.
If caching is enabled and the Cache active LED never comes on during I/O activity,
it indicates that the cache memory has failed or the battery has failed (the green
Battery LED will be off).
Note: Always use the storage-management software to check your cache memory
settings before assuming a hardware failure.
Chapter 4. Operating the storage server 43