Vivotek NR9682-v2 64-Channel NVR (No HDD) - Manual (Page 42)

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42 - User's Manual
Background Initialization
Background initialization is a check for media errors on the drives when you create a virtual
drive. It is an automatic operation that starts five minutes after you create a virtual drive. This
check ensures that striped data segments are the same on all of the drives in the drive group.
Background initialization is similar to a consistency check. The difference between the two is
that a background initialization is forced on new virtual drives and a consistency check is not.
New RAID 5 virtual drives and new RAID 6 virtual drives require a minimum number of drives
for a background initialization to start. If fewer drives exist, the background initialization does not
start. The background initialization needs to be started manually. The following number of drives
are required:
 New RAID 5 virtual drives must have at least five drives for background initialization to start.
 New RAID 6 virtual drives must have at least seven drives for background initialization to
start.
The default and recommended background initialization rate is 30 percent. Before you change
the rebuild rate, you must stop the background initialization or the rate change will not affect the
background initialization rate. After you stop background initialization and change the rebuild
rate, the rate change takes effect when you restart background initialization.2.1.7Patrol Read
Disk Striping
Disk striping lets you write data across multiple drives instead of just one drive. Disk striping
involves partition ing each drive storage space into stripes that can vary in size from a minimum
of 64 KB to 1 MB for MegaRAID controllers and 64 KB for Integrated MegaRAID controllers. The
LSISAS2108 controller allows stripe size from 8 KB to 1 MB. These stripes are interleaved in
a repeated sequential manner. The combined storage space is composed of stripes from each
drive. It is recommended that you keep stripe sizes the same across RAID drive groups.
For example, in a four-disk system using only disk striping (used in RAID level 0), segment 1 is
written to disk 1, segment 2 is written to disk 2, and so on. Disk striping enhances performance
because multiple drives are accessed simultaneously, but disk striping does not provide data
redundancy.
Segment 1
Segment 5
Segment 9
Segment 2
Segment 6
Segment 10
Segment 3
Segment 7
Segment 11
Segment 4
Segment 8
Segment 12