CLI Guide

Table 333. Creating Virtual Disks (continued)
Mandatory Options
and Arguments
Optional Parameters Valid Parameters
Arguments
Description
● 1 — RAID 1 is the simplest form of maintaining
redundant data. In RAID 1, data is mirrored or
duplicated on one or more drives.
● 5 — RAID 5 provides data redundancy by
using data striping in combination with parity
information. Rather than dedicating a drive to
parity, the parity information is striped across
all disks in the array.
● 6 — RAID 6 is an extension of RAID 5 and
uses extra parity block. It uses block-level
striping with two parity blocks distributed
across all member disks. RAID 6 provides
protection against double disk failures and
failures while a single disk is rebuilding. If
there is only one array, RAID 6 may be a
better option than a hot spare disk.
● 10 — RAID 10 is a stripe of mirrors. Multiple
RAID 1 mirrors are created, and a RAID 0
stripe is created over RAID 1 mirrors.
● 50 — RAID 50 is a dual-level array that uses
multiple RAID 5 sets in a single array. A single
hard drive failure can occur in each of the
RAID 5 without any loss of data on the entire
array. Although the RAID 50 has increased
write performance, when a hard drive fails and
reconstruction takes place, performance
decreases, data/program access is slower,
and transfer speeds on the array are affected.
● 60 — RAID 60 is a combination of RAID 6 and
RAID 0. A RAID 0 array is striped across RAID
6 elements. It requires at least 8 disks.
-ctrl -ac=cvd -
c=id -ad=
ch:targ,ch:targ,
... [or
ch:targ:encl,...]
or
controller
action=
createvdisk
controllerid= id
adisk=
channel:target:
lun,
channel:target:
lun,...
[or
channel:target:
enclosure,...]
-rp or readpolicy
ra, ara, nra, rc, nrc
CAUTION: If the controller is changed
from SCSI to RAID mode, expect data
loss to occur. Back up any data you want
to save before changing the modes.
Sets the SCSI read policy for the virtual disk.
Specify the SCSI read policy for the logical drive.
The valid arguments are:
● ra — (read-ahead) The controller reads
sequential sectors of the disk when seeking
data.
● ara — (Adaptive Read-Ahead) The controller
initiates read-ahead only if the two most
recent read requests accessed sequential
sectors of the disk. If subsequent read
requests access random sectors of the disk,
the controller reverts to No-Read-Ahead
policy. The controller continues to evaluate
whether read requests are accessing
sequential sectors of the disk and can initiate
read-ahead if necessary.
● nra — (No-Read-Ahead) The controller does
not read sequential sectors of the disk when
seeking data.
172
RAIDCFG