ESS3016X User’s Manual
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Appendix A ---Terms Explanation
Here are some terms explanations in this user’s manual.
z
NAS: It is the abbreviation for network attached system. It provides user file service via
network.
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SATA:It is the abbreviation for serial ATA. In current released Serial ATA 2.0, data
transmission speed can reach 300MB/second.
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SATA HDD: HDD adopts SATA standard. Some leading manufacturers such as Seagate,
Hitachi have already released SATA HDD.
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RAID: It is the 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. Now it consists of seven levels, ranging from RAID0
to RAID6.Besided, it has some basic RAID combination groups such as RAID10 (RAID0 and
RAID1, RAID 50(RAID 0 and RAID 5). Here is a comparison between RAID 0, RAID 1, RAID
5. In this manual, we call RAID5, RAID 1,RAID0 as RAID5 device, RAID1 device and RAID
0 device respectively.
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RAID0: RAID0 is so called Striped Disk Array without Fault Tolerance. It represents the
highest storage performance in RAID level. RAID0 is to read-write continue data in several
HDD. So, system data query will be performed in several HDDs at the same time.
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RAID1: It is also called Mirror or mirroring. Its aim is to maximally guarantee data safety and
restorable. RAID1 is to automatically copy user input data fully to other RAID1 HDDs.
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RAID 5: RAID5 does not backup the storage data. Instead, it will memorize data and
corresponding verification information to HDDs of RAID5. The data and verification
information will be backed up in different HDDs respectively. When data in one of the HDDs
is damaged, system can use the rest data and corresponding verification information to
restore the lost data.
RAID
Advantage
Disadvantage
Min HDD
Amount
Applied
zone
RAID 0
z
High read-
write
efficiency.
z
No
verification
to occupy
CPU
resources.
z
Easy to
design, use
and configure
z
No
verification
or restore
function.
z
No
data
error
tolerance.
z
Not suitable
for harsh
environment.
2
Create and
edit video
RAID 1
z
Theoretically
z
, it has double
speed.
z
100% data
redundancy
function.
z
Easy to
design, use
and configure.
z
Low HDD use
efficient.
z
High storage
cost.
z
In soft RAID1
mode,
performance
descends
gravely.
2
z
F
inancing
statistics
and data
base
financing
system.
z
Need
high
maintena
nce work.
