LSI SCSI 320-0 Configuration page 126

Logical Drive Menu,
Change Cache Policy Click on Cache to change the cache memory policy. You can choose Direct
or Cached.
Change Read Policy Click on Read to change the Cache Read Policy. You can choose Normal,
Read Ahead, or Adaptive Read Ahead.
Read Policy
Normal The MegaRAID controller does not use read-ahead for the selected
logical drive.
Read Ahead The MegaRAID controller uses read-ahead for the selected logical
drive. This is the default setting.
Adaptive The MegaRAID controller begins using read-ahead if the two most
Read Ahead 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.
Change Write Policy Click on Write to change the Cache Write Policy. The settings are:
Setting
Write Back
Write Thru
Virtual Sizing Click on this option to enable or disable the Virtual Sizing Option. See Chapter
9 for more information about virtual sizing.
Note: Virtual sizing is not supported in Windows 2000.
Add Capacity Click on this option to add additional drive(s) to the specified logical drive. First
click on the drive icon for each physical drive to be added. Then click on the
icon for the logical drive to be added to. Then select Add Capacity from the
Logical Drive menu. Click on OK when prompted to confirm the new logical
drive configuration. You can also select a new RAID level for the selected
logical drive when the Select RAID Level prompt appears. You can select any
RAID level that is not grayed out. Click on OK to complete the operation. See
Chapter 9 for more information about online capacity expansion.
Note: Virtual sizing is not supported in Windows 2000.
The physical drive must be in the READY state before it can be
No operation can be started while a drive is being reconstructed.
MegaRAID Configuration Software Guide
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Continued
Description
The MegaRAID controller sends a data transfer completion signal to the host
when the controller cache has received all the data in a transaction.
The MegaRAID controller sends a data transfer completion signal to the host
when the disk array has received all the data in a transaction. This is the
default setting. Write-through caching has a data security advantage over
write-back caching. Write-back caching has a performance advantage over
write-through caching. If running Windows NT, you should not use write-
back for any logical drive that is to be used as a Novell NetWare volume.
Important
added to a logical drive.
Description