DATOptic RM12-S6.TB - Rackmount - Manual (Page 21)

WEB BROWSER-BASED CONFIGURATION
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•Volume Write Protection
When "Volume Write Protection" is enabled on the "Modify
Volume Set", host commands fail if they are issued to a volume
in that RAID controller and attempt to modify a volume's data
or attributes. Volume Write Protection is used primarily for
customer-initiated disaster recovery testing.
• Volume IO Mode:
The Cache IO and Direct IO cache policies apply to read on a
specific virtual disk. The volume IO mode options are as follows:
- Cache Io
Specifies that all reads are buffered in the controller cache
memory.
- Direct Io
Specifies that reads are not buffered in cache memory. When
using direct IO mode, data is transferred to the controller cache
memory and the host system simultaneously during a read
request.
If a subsequent read request requires data from the same data
block, it can be read directly from the controller cache memory.
• Tagged Command Queuing
The “Enabled” option is useful for enhancing overall system
performance under multi-tasking operating systems. The
Command Tag (Drive Channel) function controls the SATA
command tag queuing support for each drive channel. This
function should normally remain “Enabled”. “Disabled” this
function only when using SATA drives that do not support
command tag queuing.
• SCSI Channel/SCSI ID/SCSI Lun
SCSI Channel: The 6Gb/s SATA RAID controller function is simu-
lated as an external SCSI RAID controller. The host bus is repre-
sented as a SCSI channel. Choose the SCSI Channel.
SCSI ID: Each SCSI device attached to the SCSI card, as well
as the card itself, must be assigned an unique SCSI ID number.
A SCSI channel can connect up to 15 devices. The 6Gb/s SATA
RAID controller is a large SCSI device. Assign an ID from a list
of SCSI IDs.