Dell DC, 3, User Manual

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PERC 3 BIOS Configuration Utility 171
the criteria are not met, the span setting makes no difference for the
current logical drive.
12
Highlight a spanning option and press <Enter>.
13
Set the logical drive size.
14
Move the cursor to Size and press <Enter>.
By default, the logical drive size is set to all available space in the
array(s) being associated with the current logical drive, accounting for
the span setting.
15
Open the Advanced Menu to set the remaining options:
16
Set the Stripe Size .
Stripe size specifies the size of the segments written to each disk in a
RAID 1 or 5 logical drive. You can set the stripe size to 2 KB, 4 KB, 8
KB, 16 KB, 32 KB, 64 KB, or 128 KB. A larger stripe size produces
higher read performance, especially if your computer does mostly
sequential reads. However, if you are sure that your computer does
random read requests more often, select a small stripe size. The
default stripe size is 64 KB.
17
Set the Write Policy .
Write Policy sets the caching method to write-back or write-through.
– In Write-back caching , the controller sends a data transfer
completion signal to the host when the controller cache has
received all the data in a transaction. This setting is recommended
in standard mode.
– In Write-through caching , the controller sends a data transfer
completion signal to the host when the disk subsystem has
received all the data in a transaction. This is the default setting in
cluster mode.
Write-through caching has a data security advantage over write-back
caching, whereas write-back caching has a performance advantage over
write-through caching.
18
Set the Read Policy .
Read-ahead This option enables the SCSI read-ahead feature for the
logical drive. You can set this parameter to No-Read-Ahead , Read-
ahead , or Adaptive . The default setting is Adaptive .