The team and their topics along Roll Numbers.

Takasur Azeem

R.A.I.D

BITF13A002

M.Imran

NAS

BITF13A014

Hamza Yaqoob

Cloud Storage

BITF13A029

R.A.I.DBy : Takasur AzeemRoll No : BITF13A002

What is R.A.I.D?• In 1987, Patterson, Gibson and Katz at the University of California Berkeley, published a paper entitled "A Case for Redundant Arrays of Inexpensive Disks (R.A.I.D)“

•Hardware R.A.I.D

• Software R.A.I.D

Arrays of Inexpensive Disks•A lot of PC disk development

•Used today in what is called R.A.I.D level 0 (explanation to come)

S.L.E.D.

• S.L.E.D. – Single Large Expensive Disks

•Capacity: good

•Performance: not-keeping-up with CPU

•Solution?

Redundant Arrays of Inexpensive Disks• Adding redundancy for error correction

•Different Levels of R.A.I.D. features vs. performance:

i. R.A.I.D 0 – Blocks Striping

ii. R.A.I.D 1 – Mirroring

iii. R.A.I.D 2 – Hamming Code

iv. R.A.I.D 3 – Single Check Disk per Group

v. R.A.I.D 4 – Independent Reads/Writes

vi. R.A.I.D 5 – No Single Check Disk

vii.R.A.I.D 6 – Extends R.A.I.D 5 by adding an additional parity block

R.A.I.D 0 – Blocks Striping• Not technically a R.A.I.D level

• Very good performance, but at a price…

• No mirror no parity.

• Recommended Applications :

i. Video Production and Editing

ii. Image Editing

iii. Any application requiring high bandwidth

R.A.I.D 1 - Mirroring•  Data are written identically to two (or more)

drives

• Recommended Applications

i. Accounting

ii. Payroll

iii. Financial

iv. Any application requiring very high availability

R.A.I.D 2 – Hamming Code• Uses bit-level striping and

hamming code ECC in an effort to reduce errors

• Example…

• Massive disk requirements and poor performance on small data kept this R.A.I.D level more theoretical then practical

R.A.I.D 3 – Byte Level Stripping• This uses byte level striping. i.e. Instead of striping

the blocks across the disks, it stripes the bytes across the disks.

• Example…

• In the diagram B1, B2, B3 are bytes. p1, p2, p3 are parities.

R.A.I.D 4 – Independent Reads• Just like R.A.I.D 3 but stripes on the file (blocks)

level

• Fast reads: theoretically 1 per disk concurrently

• Slow writes: have to read corresponding sectors on each disk to calculate new parity

R.A.I.D 5 – Blocks Stripped, Distributed Parity• Check disk information is distributed across all data

disks – no more check disk bottleneck

• Some Key Points :

i. Minimum 3 disks.

ii. Good performance ( as blocks are striped ).

iii. Good redundancy ( distributed parity ).

• Recommended Applications

i. Database servers

i. WWW, E-mail, and News servers

R.A.I.D 6 – Blocks Stripped – Two Distributed Parities.• Just like RAID 5, this does block level striping. However, it uses dual

parity.

• In the above diagram A, B, C are blocks. p1, p2, p3 are parities.

• This creates two parity blocks for each data block.

• Can handle two disk failure

• This RAID configuration is complex to implement in a RAID controller, as it has to calculate two parity data for each data block.

R.A.I.D 10 – Blocks Mirrored, Blocks Stripped• Minimum 4 disks.

• This is also called as “stripe of mirrors”

• Excellent redundancy ( as blocks are mirrored )

• Excellent performance ( as blocks are striped )

• If you can afford the dollar, this is the BEST option for any mission critical applications (especially databases).

Conclusions• R.A.I.D offers a cost effective alternative to SLED

through the use of data striping, mirroring, and parity

• Different R.A.I.D “levels” can be chosen to suit different functions for the computer.

MUHAMMAD IMRANBS(IT) afternoon

BITF13A014

AGENDA

• NAS(Network attached storage)

What is NAS?• NAS is a file level storage that is connected to a network to

provide a file data access to heterogeneous (systems that use more than one kind of processor) group of clients.

BENEFITS OF (NAS)• Improved efficiency

• Improved flexibility

• Centralized storage

• Security

• scalability

NAS protocols• Andrew File System (AFS)

• R sync

• Universal plug and play

• Network File System (NFS)

TYPES OF NAS

• Consumer level NAS

• Small medium business NAS

• Enterprise NAS storage

• Clustered NAS

THE END• THANKS FOR WATCHING……