RAID
RAID
What is the Meaning of RAID
RAID? - RAID : Redundant Array of Independent Disks (Disk Array)
- Its a simple! Make a single disk from multiple disks.
Purpose of using RAID
- Make a huge size disk from multiple normal disks.
COST
- Single huge size disk is VEEEEEEEEERY expensive.
- BUT if you use RAID system, according to circumstances, you can SAVE your money!
RECOVERABLE(Redundancy)
-Imagine the situation that your disks have some error.
-If you use a single huge size disk, in the majority of cases, you get ready to say good bye to your disk.
-BUT if you use RAID system, according to used RAID level, you can deliver your data from ERROR!
PERFORMANCE
-You can get a good performance using RAID system than using a sing huge size disk.
-Refer to the image next slide for details.
RAID
What is the If system can be recorded to HDD 1unit data/sec
RAID?
5s 5s
9 10 5
4s 4s
7 8 4
3s 3s
5 6 3
2s 2s
3 4 2
1s 1s
1 2 1
RAID system with 2 HDDs Normal system with single HDD
- Can record 10 units during 5 sec - Can record 5 units during 5 sec
RAID system can record more data during same time than using single HDD
RAID
Simple step
for saving Not-used
data on your
RAID system
Usable area
HDD1 HDD2 HDD3 HDD1 HDD2 HDD3
(2TB) (500GB) (1TB) (500GB) (500GB) (500GB)
1 2 Normalize
3 4
Cut HDDs usable area to unit size
Save your data!
RAID
LEVEL of RAID
Min. # of Performance HDD usage
- RAID 0 HDDs
Redundancy
efficiency
Read(Normal) Write(Normal) Read(Error) Write(Error)
2 N/A High High N/A N/A 100%
RAID 0 [Example of RAID 0]
-Step 1. Cut your data into unit sized pieces
-Step 2. Save unit data onto each HDDs in rotation
7 8
Feature 5 6
-No HDDs for redundancy : If some error occurs on
3 4
specific HDD, you are unable to resuscitate your data.
1 2
RAID
LEVEL of RAID
Min. # of Performance HDD usage
- RAID 1 HDDs
Redundancy
efficiency
Read(Normal) Write(Normal) Read(Error) Write(Error)
Half # of
2 High Middle Middle High 50%
HDDs
RAID 1 : Mirroring [Example of RAID 1]
-Step 1. Cut your data into unit sized pieces
-Step 2. Save unit data onto HDD
4 4
-Step 3. Copy your saving data to other HDD
3 3
Feature
2 2
-2 HDDs make a single array.
-Half number of HDDs used for redundancy.
1 1
-If you organize total 4TB HDDs for RAID, ONLY you
can save maximum 2TB size data on your RAID
system.
RAID
LEVEL of RAID
Min. # of Performance HDD usage
- RAID 4 HDDs
Redundancy
efficiency
Read(Normal) Write(Normal) Read(Error) Write(Error)
3 1 HDD High Low Normal Low 67~94%
(Sometimes, Very Low)
RAID 4 [Example of RAID 4]
-Step 1. Cut your data into unit sized pieces
A1 A2 A3 Ap
-Step 2. Save unit data onto each HDDs in rotation
B1 B2 B3 Bp
-Step 3. Make a parity unit data and save that onto 1
C1 C2 C3 Cp
HDD
D1 D2 D3 Dp
Feature
-Parity unit has information of other unit data.
(Ex) From example fig., Ap has information of A1, A2 and A3
-1HDD used for redundancy.
-All of parity units are saved on same HDD.
(You can resuscitate only 1 HDD from error situation.)
RAID
LEVEL of RAID
Min. # of Performance HDD usage
- RAID 5 HDDs
Redundancy
efficiency
Read(Normal) Write(Normal) Read(Error) Write(Error)
3 1 HDD High Low Low Low 67~94%
RAID 5 [Example of RAID 5]
-Step 1. Cut your data into unit sized pieces
A1 A2 A3 Ap
-Step 2. Save unit data onto each HDDs in rotation
B1 B2 Bp B3
-Step 3. Make a parity unit data and save that onto
C1 Cp C2 C3
each HDDs in rotation
Dp D1 D2 D3
Feature
-Parity unit has information of other unit data.
(Ex) From example fig., Ap has information of A1, A2 and A3
-Some parts of each HDDs used for redundancy.
(You can resuscitate only 1 HDD from error situation.)
RAID
LEVEL of RAID
Min. # of Performance HDD usage
- RAID 6 HDDs
Redundancy
efficiency
Read(Normal) Write(Normal) Read(Error) Write(Error)
4 2 HDDs High Low Low Low 50~88%
RAID 6 [Example of RAID 6]
-Step 1. Cut your data into unit sized pieces
A1 A2 A3 Ap Aq
-Step 2. Save unit data onto each HDDs in rotation
B1 B2 Bp Bq B3
-Step 3. Make a parity unit data and save that onto
C1 Cp Cq C2 C3
each HDDs in rotation
Dp Dq D1 D2 D3
-Step 4. One more Step 3! Eq E1 E2 E3 Ep
Feature
-Parity unit has information of other unit data.
(Ex) From example fig., Ap and Aq have information of A1,
A2 and A3
-There are 2 parity units for same information.
-Some parts of each HDDs used for redundancy.
(You can resuscitate 2 HDDs from error situation.)
RAID mode
WITH SAMSUNG TECHWIN PRODUCT
RAID
RAID with
Max. # of Min. # of HDD
Samsung Supported RAID Level
equipable internal HDD for using RAID mode
Product
RAID 5 8 4
SRN-1000
-Support after version 1.40_130827
-Able to use 1HDD for spare(if organize RAID with more than 4 HDDs)
Total # of HDD for # of HDD for # of HDD for
organize RAID recording spare
4 4 0
5 4 1
6 5 1
7 6 1
8 7 1
-Able to make maximum 1 array with internal HDDs
-Recording bandwidth with RAID mode is 64 Mbps
RAID
RAID with
Max. # of Min. # of HDD
Samsung Supported RAID Level
equipable internal HDD for using RAID mode
Product
RAID 5 5
SRN-4000 12
RAID 6 6
-Support all version
-Able to use 1HDD for spare
-Able to make maximum 2 arrays with internal HDDs
SRN-4000 with RAID 5
Max. recording bandwidth = 400Mbps (When using recording ONLY)
1 HDD on each array is recoverable
SRN-4000 with RAID 6
Max. recording bandwidth = 300Mbps
(When using recording ONLY)
2 HDDs on each array is recoverable
