Dell 3 Computer Hardware User Manual


 
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 specifies that the controller does not use read-ahead for
the current logical drive.