Asus PIKE 2208 - Manual (Page 38)

2-24 Chapter 2: RAID configuration
Using Manual Configuration: RAID 6
RAID 6 is similar to RAID 5 (drive striping and distributed parity), except that
instead of one parity block per stripe, there are two. With two independent parity
blocks, RAID 6 can survive the loss of any two drives in a virtual drive without
losing data. Use RAID 6 for data that requires a very high level of protection from
loss.
RAID 6 is best suited for networks that perform a lot of small input/output (I/O)
transactions simultaneously. It provides data redundancy, high read rates, and
good performance in most environments.
In the case of a failure of one drive or two drives in a virtual drive, the RAID
controller uses the parity blocks to recreate all of the missing information. If two
drives in a RAID 6 virtual drive fail, two drive rebuilds are required, one for each
drive. These rebuilds do not occur at the same time. The controller rebuilds one
failed drive, and then the other failed drive.
When you select Manual Configuration and click Next, the Drive Group
Definition screen appears. You use this screen to select drives to create drive
groups.
1. Hold while you select at least three ready drives in the Drives panel
on the left.
2. Click Add To Arrary to move the drives to a proposed drive group
configuration in the Drive Groups panel on the right.
3. Select a preferred power save mode. The power save mode can be Max,
Max without cache, Auto, None, and Controller defined. If you need to
undo the changes, click Reclaim.
4. After you finish selecting drives for the drive group, click Accept DG.
5. Click Next. The Span Definition screen appears. Select one of the available
drive groups, and then click Add to SPAN.
6. When finish, click Next. The Virtual Drive Definition screen appears. You
use this screen to select the RAID level, strip size, read policy, and other
attributes for the new virtual drives.
7. Change the virtual drive options from the defaults listed on the screen as
needed.
Here are brief explanations of the virtual disk options:
• RAID Level: The drop-down menu lists the possible RAID levels for the
virtual drive. Select RAID 6.
• Strip Size: The strip size specifies the size of the segment written to
each disk in a RAID configuration. You can set the strip size up to 1 MB.
A larger strip size produces higher read performance. If your computer
regularly performs random read requests, choose a smaller strip size.
The default is 256 KB.