Toshiba Magnia 560S - Manual (Page 126)

Configuring Arrays and Logical Drives 108
MegaRAID BIOS Configuration Utility
6. Press <Enter> when you are finished creating the current array.
The logical drive configuration screen displays the logical drive that is currently
being configured as well as any existing logical drives. The column headings are:
LD - The logical drive number
RAID - The RAID level
Size - The logical drive size
#Stripes - The number of stripes (physical drives) in the associated physical array
StrpSz -The stripe size
DriveState - The state of the logical drive
7. Highlight RAID and press <Enter> to set the RAID level for the logical drive.
The available RAID levels for the current logical drive display.
8. Select a RAID level and press <Enter> to confirm.
See Chapter3, RAID Levels for your board for an explanation of the RAID levels.
9. Set the Stripe Size on the Advanced Menu.
Stripe size specifies the size of the segments written to each disk in a RAID 0, 5, 10,
or 50 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 read requests more often, choose a small stripe size. The default is 64
KB.
10. Set the Write Policy on the Advanced Menu.
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
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.
11. Set the Read Policy on the Advanced Menu.
Read-policy enables the SCSI read-ahead feature for the logical drive. You can set
this parameter to Normal, Read-ahead, or Adaptive.
- Normal specifies that the controller does not use read-ahead for the current
logical drive.
- Read-ahead specifies that the controller uses read-ahead for the current logical
drive.
- Adaptive specifies that the controller begins using read-ahead if the two most
recent disk accesses occurred in sequential sectors. If all read requests are
random, the algorithm reverts to Normal; however, all requests are still
evaluated for possible sequential operation. This is the default setting.