Dell DC, 3, User Manual

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196 Dell Manager
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1
Select Objects— > Physical Drive and press <Enter>.
The Physical Drive Selection Menu displays.
2
Highlight a drive on the Physical Drive Selection Menu using the
arrow keys and press <Enter>.
The action menu for the physical drive displays.
3
Use the arrow key to select Make HotSpare , then press <Enter>.
The indicator for the selected physical drive changes to HOTSP .
Parameters
The parameters contain the settings for the stripe size, write policy, read
policy and cache policy. The policies and default settings are described in
the following information.
• 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
better read performance, especially if your computer does mostly
sequential reads. If you are sure that your computer does random reads
more often, select a small stripe size. The default stripe size is 64 KB.
• Write Policy specifies the cache write policy. You can set the write
policy 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 is the default setting.
– 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.
Write-through caching has a data security advantage over write-back
caching. Write-back caching has a performance advantage over write-
through caching.
• Read Policy specifies that the SCSI read-ahead feature is used for the
logical drive. You can set this parameter to Normal , Read-ahead , or
Adaptive . The default setting is Adaptive .
– Normal s pecifies that the controller does not use read-ahead for
the current logical drive.