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About RAID

Advantages of RAID

There are three reasons you might want aRAID system o drives.

1. You need tons o storage space and you need it tobe ast. (RAID 0)

2. You want to instantaneously and automaticallybackup your data. (RAID 1)

3. You want both. (RAID 5)

RAID is an acronym or Redundant Array o Independent Disks. With RAID enabled on a storagesystem you can connect two or more drives in the system so that they act like one big ast drive orset them up so that one drive in the system is used to automatically and instantaneously duplicate (ormirror) your data or real-time backup.

RAID 0

RAID 1

RAID 5

Fault Tolerance

Data

RAID Mode Comparison

Which RAID mode should I use?

1. Speed (RAID 0)Set in high-perormance mode (also called striped mode or RAID 0) the storage system gives youthe power you need when youre:

Designing huge graphics and need a lightning-ast Photoshop scratch space.Recording large DV les while maintaining clean audio perormance.Editing DV or HD video and want a smooth work fow with no dropped rames.

Rendering complex 3D objects or special eects.Perorming disk-intensive database operations.Driven to be the rst geek on your block with a computer so ast it blows your socks o.

Why is RAID 0 so ast? Its a bit complicated, but suce it to say that two or more heads, or inthis case, drives, are better than one. Picture multiple hoses lling a bucket at the same time orseveral men bailing a boat and you can understand why two or more drives striped are aster thanone. Data is saved (striped) across the drives and accessed in parallel by all the drives so youget higher data transer rates on large data accesses and higher input/output rates on small dataaccesses.

2. Data protection (RAID 1)Set the system to data protection mode (also known as mirrored mode or RAID 1) and thecapacity is divided in hal. Hal o the capacity is used to store your data and hal is used or aduplicate copy.

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Western Digital, WD, the WD logo, Put Your Lie On It, and My Book are registered trademarks in the U.S. and other countries; and WD ShareSpace,Studio Edition, Mirror Edition and World Edition are trademarks o Western Digital Technologies, Inc. Other marks may be mentioned herein that belongto other companies. Not all products or capacities are available in all regions o the world. Pictures shown may vary rom actual products. All product andpackaging specications subject to change without notice.

As used or storage capacity, one megabyte (MB) = one million bytes, one gigabyte (GB) = one bil lion bytes, and one terabyte (TB) = one trillion bytes.

Total accessible capacity varies depending on operating environment.

2009 Western Digital Technologies, Inc. All rights reserved. 4178-705028-A01 Jun 2009

WDs Storage Systems with RAID

WD ShareSpace My Book

Studio Edition II

My Book

Mirror EditionMy Book

World Edition II

RAID 0 (Striped) u u u u

RAID 1 (Mirrored) u u u u

RAID 5 u

uDeault confguration

uCapable confgurations

Why do I want that kind o redundancy? Its your data, your amily pictures, your movie o babysrst steps, your rst novel. Is it important? You decide. I it is, then RAID mirroring is or you.

3. Data protection and speed (RAID 5)In systems with three or more drives, (like our WD ShareSpace Network Storage System)

we recommend that you set the system to RAID 5. This gives you the best o both worlds: astperormance by striping data across all drives; data protection by dedicating a quarter o eachdrive to ault tolerance leaving three quarters o the system capacity available or data storage.