Vivotek NR9682-v2 64-Channel NVR (No HDD) - Manual (Page 44)

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44 - User's Manual
A RAID 5 drive group combines distributed parity with disk striping. If a single drive fails, it can
be rebuilt from the parity and the data on the remaining drives. An example of a RAID 5 drive
group is shown in the following figure. A RAID 5 drive group uses parity to provide redundancy
for one drive failure without duplicating the contents of entire drives. A RAID 6 drive group also
uses distributed parity and disk striping, but adds a second set of parity data so that it can
survive up to two drive failures.
Parity Type Description
Dedicated The parity data on two or more drives is stored on an additional disk.
Distributed The parity data is distributed across more than one drive in the system.
Segment 1
Segment 7
Segment 13
Segment 2
Segment 8
Segment 14
Segment 3
Segment 9
Segment 15
Segment 4
Segment 10
Parity (11 to 15)
Segment 5
Parity (6 to 10)
Segment 11
Parity (1 to 5)
Segment 6
Segment 12
Segment 19
Segment 25
Parity (26 to 30)
Segment 20
Parity (21 to 25)
Segment 26
Parity (16 to 20)
Segment 21
Segment 27
Segment 16
Segment 22
Segment 28
Segment 17
Segment 23
Segment 29
Segment 18
Segment 24
Segment 30
Disk Spanning
Disk spanning allows multiple drives to function like one big drive. Spanning overcomes lack
of disk space and simplifies storage management by combining existing resources or adding
relatively inexpensive resources. For example, four 20-GB drives can be combined to appear
to the operating system as a single 80-GB drive.Spanning alone does not provide reliability or
performance enhancements. Spanned virtual drives must have the same stripe size and must
be contiguous. In the following figure, RAID 1 drive groups are turned into a RAID 10 drive
group.
Spanning two contiguous RAID 0 virtual drives does not produce a new RAID level or add
fault tolerance. It does increase the capacity of the virtual drive and improves performance by
doubling the number of spindles.
Spanning for RAID 00, RAID 10, RAID 50, and RAID 60 Drive Groups
The following table describes how to configure RAID 00, RAID 10, RAID 50, and RAID 60
drive groups by spanning. The virtual drives must have the same stripe size and the maximum
number of spans is 8. The full drive capacity is used when you span virtual drives; you cannot
specify a smaller drive capacity.