Planning: RAID Controller Modules 35
Storage Array Thermal Shutdown
The system automatically shuts down when system temperature exceeds the
safe threshold. The battery backup unit protects against data loss by
providing power to offload cache to non-volatile memory in the event of
power loss. It is not necessary to shut down any MD1200 Series expansion
enclosures attached to the storage array when thermal shutdown occurs.
Temperature threshold values determine the temperature at which shutdown
occurs. These thresholds cannot be changed.
System Password Reset
The storage array password can be reset if it is forgotten. To reset the password,
push and hold down the password reset switch for at least 5 seconds. The
password is delet ed. See Figure 3-1 to locate the pa ssword reset swi tch.
The RAID controller module allows you to change the password. For more
about setting your password, see "Setting a Password" on page73.
NOTE: The reset switch can be accessed by using a small object such as the tip of
a pen.
Cache Functions and FeaturesCache Mirroring
Cache mirroring function copies accepted host-write data from the primary
controller to the partner controller. This action ensures that host-write data is
safely mirrored to the partner controller before successful completion status is
returned to the host. If a controller fails, the surviving controller safely retains
all mirrored data. Cache mirroring is enabled by default.
Table 3-2. Shutdown Threshold Type
Threshold Temperature Exceeding Event Description
Nominal failure threshold A critical event is set.
Maximum failure threshold Shutdown of the system power supplies occurs
within three minutes.
Shutdown threshold Shutdown of the system power supplies occurs
within five seconds.
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