Dell 3 User Manual

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PERC 3 BIOS Configuration Utility

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– CanSpan: Array spanning is enabled for the current logical drive.

The logical drive can occupy space in more than one array.

– NoSpan: Array spanning is disabled for the current logical drive.

The logical drive can occupy space in only one array.

PERC 3 supports spanning for RAID 1 and RAID 5 arrays only. You can

span two or more contiguous RAID 1 logical drives into a RAID 10

array, or two or more contiguous RAID 5 logical drives into a RAID 50

array.
For two arrays to be spanned, they must have the same stripe width

(they must contain the same number of physical drives) and they must

be consecutively numbered. For example, assuming Array 2 contains

four disk drives, it can be spanned only with Array 1 and/or Array 3,

and only if Arrays 1 and 3 also contain four physical drives.
If the two criteria for spanning are met, PERC 3 automatically

activates spanning. If the criteria are not met, the span setting makes

no difference for the current logical drive.

Highlight a spanning option and press .

Set the logical drive size.

Move the cursor to Size and press .
By default, the logical drive size is set to all available space in the

array(s) associated with the current logical drive, accounting for the

span setting.

Open the Advanced Menu to set the remaining options.

Set the Stripe Size.
Stripe size specifies the size of the segment 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 your computer does random read

requests more often, choose a smaller stripe size. The default is 64 KB.

Set the Write Policy.
Write Policy specifies the cache write policy. You can set the write

policy to Write-back or Write-through: