Disable or Enable Read-Ahead Cache
Mode: These choices are available in
the Information mode only. When
read-ahead cache is set to Enabled
(default setting), the ServeRAID
controller transfers data from a disk to
its local cache in increments equal to
the stripe-unit size. This provides
excellent overall performance when
workloads are steady and sequential.
However, if the workload is random or
the system I/O requests are smaller than
the stripe-unit size, reading ahead to the
end of the stripe might degrade
performance. When read-ahead cache
is set to Disabled, the ServeRAID
controller transfers data from a disk to
local cache in increments equal to the
system I/O request size, without reading
ahead to the end of the stripe.
Change the Rebuild Rate: This choice
is available in the Information mode
only. You can select this choice to set
the priority for Rebuild operations to
High (default), Medium, or Low.
–
When the rebuild rate is set to
High, the rebuild I/O request gets
high priority in the execution order.
–
When the rebuild request is set
from High to Medium in a heavily
loaded system, it can increase the
rebuild time, but provide better
system performance.
–
When the rebuild request is set
from High or Medium to Low in a
moderate to heavily loaded system,
it can increase the disk rebuild
time, but provide better system
performance.
Change the Stripe-Unit Size: This
choice is available in the Information
mode only.
Attention
After you configure an array and
store data on the logical drives, you
cannot change the stripe-unit size
without destroying data in the
logical drives.
The stripe-unit size is the amount of
data written on a given disk before
writing on the next disk. To maximize
the overall performance, choose a size
Netfinity 5500 M20 - Type 8662
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