MicroNet Technology MaxNAS manual Appendix B RAID Level Comparison Table

B-RAID Level Comparison Table

Appendix B: RAID Level Comparison Table

RAID

Description

Min.

Max.

Capacity

Data

Data

I/O

Level

Drives

Drives

Reliability

Transfer Rate

Request Rates

Span

Also known as disk spanning. Data

1

4

(N)

No data protection

Same as a single disk

same as a single disk

is distributed sequentially to all

Disks

drives. There is no data protection.

0

Also known as striping

1

4

(N)

No data

Very High

Very High for

Data

distributed

across

multiple

Disks

Protection

Both Reads and Writes

drives in the array simultaneously.

There is no data protection

1

Also known as mirroring

2

4

1/(N )

Lower than

RAID

6,

Reads are higher

Reads

are

twice

faster

All data replicated on N Separated

Disks

Higher than RAID 5

Than a single disk;

than a single disk;

disks. N is always a multiple of 2.

This is a high availability Solution,

Writes similar to a sin-

Write

are similar

to

a

but due to the 100% data duplication,

gle disk

single disk.

it is also a costly solution.

10

Also known as striped mirroring. Data

4

4

1/2 (N)

Lower than

RAID

6,

Reads

are

similar

to

Reads

are

similar

to

and parity information is subdivided

Disks

higher than RAID 5

RAID 0

RAID 0

and distributed across all disks. This

is a high availability Solution, but

Writes

are

similar

to

Writes are similar to sin-

due to the 100% data duplication, it

single disk

gle disk

is also a costly solution.

5

Also

known

Block-Interleaved

3

5

(N-1)

Lower than RAID 1, 10

Reads are similar to

Reads are similar to

distributed Parity. Data and parity

Disks

RAID 0;

RAID 0;

information

is

subdivided

and

Higher than

a single

distributed across all disk. Parity

drive

Writes are slower than

Writes are slower than a

must be the equal to the smallest

RAID 0

single disk.

disk capacity in the array. Parity

information normally stored on a

dedicated parity disk.

6

Also known as dual parity. Similar

4

5

(N-2

Highest Reliability

Reads are similar to

Reads are similar to

to RAID 5, but does two different

Disks)

RAID 0;

RAID 0;

parity computations or the same

computation on overlapping subsets

Writes are slower than

Writes are slower than a

of the data. The RAID 6 can offer

RAID 5

single disk.

fault

tolerance

greater that

RAID

1 or RAID 5 but only consumes

the capacity of 2 disk drives for

distributed

parity

data

reliability

similar to RAID 0.

MaxNAS Owner’s Manual 60