365
Appendix H RAID Introduction
Appendix H-1 About RAID
RAID is an abbreviation for Redundant Array of Independent Disks.
It is to combine several independent HDDs (physical HDD) to form a HDD group (logic HDD) to provide
more
storage
capacity
and
data
redundancy.
Right
now
system
supports
RAID0/RAID1/RAID5/RAID10.
Each level has different data protection, data usage and performance
levels. Please refer to the following sheet for detailed information.
Appendix H-2 RAID Level
RAID
Level
Note
Min HDD
Needed
RAID0
RAID0 has no redundancy and no verification function.
RAID0 has at least two HDDs. It uses two HDDs (or more)
to one and the data is saved in each HDD. The read-write
speed
multiples
since
the
bandwidth
multiples.
Theoretically speaking, the speed of the RAID0 is the N of
the each HDD. The security level decrease N since the
data is saved in different HDD blocks instead of saving in
one HDD. That is to say, once any of the HDD is damaged,
system loses all data.
RAID0 just purely enhances read-write performance while
there is no data security guarantee. So, RAID0 is the most
vulnerable RAID type and there is no redundancy function.
Any HDD physical malfunction may affect all data. So,
RAID 0 is not for the environment of high data security
requirements.
2
RAID1
RAID1 is a safe RAID mode. It realizes data redundancy
function via HDD data mirroring, so there are backup data
on these two HDDs respectively. When one HDD is
malfunction, system can read data from the other HDD. So
RAID 1 presents high redundant function. But the write
performance may be low since the data needs to be written
twice. RAID1 is an ideal option for the environment of high
security concern instead of the speed.
RAID1 has the highest unit cost in all the RAID types. But it
provides general high data security and operation function.
When one physical HDD is malfunction, system can auto
switch to the mirroring HDD to read and write instead of
rebuilding the invalid data.
When one HDD is malfunction, you can just replace the
damaged HDD. If the other HDD is damaged too before
2
Summary of Contents for HCVR82**A-S3 Series
Page 1: ...Dahua HDCVI Standalone DVR User s Manual Dahua HDCVI Standalone DVR User s Manual V1 1 0 ...
Page 84: ...72 Figure 4 44 Figure 4 45 ...
Page 102: ...90 Figure 4 73 Figure 4 74 ...
Page 104: ...92 Figure 4 76 Figure 4 77 ...
Page 120: ...108 Figure 4 93 Check a file name double click file or click to play ...
Page 158: ...146 Figure 4 135 Figure 4 136 ...
Page 167: ...155 Figure 4 145 Click Draw button to draw the tripwire See Figure 4 146 Figure 4 146 ...
Page 183: ...171 Figure 4 162 Figure 4 163 ...
Page 190: ...178 Figure 4 171 Figure 4 172 ...
Page 191: ...179 Figure 4 173 Figure 4 174 ...
Page 199: ...187 4 186 and Figure 4 187 Figure 4 186 Figure 4 187 ...
Page 275: ...263 Figure 5 60 Figure 5 61 ...
Page 289: ...277 Figure 5 77 Click to draw the rule See Figure 5 78 Figure 5 78 ...
Page 349: ...337 ...
Page 358: ...346 the sound ventilation Please check and maintain the device regularly ...
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