RAID 0 Retrieval: Frequently Asked Questions  
  RAID 0 volume sets are one of the most popular RAID levels among business and home users. Compared to a single disk volume (non-RAID configuration), there are some benefits of a RAID 0 configuration. But there are some risks and disadvantages as well. These frequently asked questions and answers will help you gain a general knowledge of RAID 0 and what you can do if our RAID 0 fails.

What is RAID level zero?

RAID 0 is a striped volume set without parity. Contrary to the definition of RAID (“redundant array of independent disks”) there is no redundancy with a RAID 0. A RAID 0 volume consists of two or more drives that are accessed as one.

What is a striped volume set?

Disk striping means that data is written across the multiple member drives evenly (“striped”). That is, whenever you write a file onto a RAID volume that is larger than the block size, a piece of that file will be distributed across multiple drives.

What are the advantages of RAID 0?

The main benefit of RAID 0 is performance. Each hard disk drive only has one read/write head, so when multiple processes are trying to access the drive, they’ll have to queue up. With a RAID 0, you can have more read/write processes happening in parallel. The result is faster retrieval and writing of data on the system. In a way, it’s a bit like the difference between a single core processor and a dual core processor.

What are the disadvantages of RAID 0?

While RAID 0 offers performance advantages, it does not provide any fault tolerance. That is, if one drive fails in a RAID 0, the entire volume becomes unreadable. This is true no matter how many drives you have in the RAID 0 configuration. When compared to other RAID levels that do have fault tolerance, the disadvantage is clear. But even when you compare it to a single disk drive, this could be seen as a drawback, since you now have two potential points of failure.

How do you recover data from a failed RAID 0?

Data recovery from a RAID 0 depends on the point of failure. If the RAID controller has failed, then the RAID 0 should be recoverable in its entirety by replacing the RAID controller. If a disk has failed, then things become more difficult. With hard disk drives, you will sometimes get early warning signs of impending mechanical failure. In some cases, you may even have brief periods of time when the disk works properly. If this is the case, then you should shut down the RAID and remove the disks. Attempt to create a block-level copy of every sector on the failed or failing disk and copy it to an image. Then, you can use virtual RAID software to rebuild the RAID configuration using your original settings. Use the image of the drive, rather than the actual drive, as you attempt to run data recovery operations and attempt repairs of the disk. This prevents further data loss as the hard drive’s physical components continue to worsen.
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