[SHENGTON]

Hello, good evening.

I don't really understand the difference of these three RAIDs. I search it in the net but non of the links give the exact answer or direct answer of the differences of the three RAIDs. So I just post here just hoping if someone could enlighten me and explain it briefly the differences of 3 RAIDs.

So, what's the difference between RAID 2, 3, and 4?

Much better if there are examples.

Thanks advance.

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I think these two sites explain it well:

http://www.acnc.com/04_01_00.html
http://www.accs.com/.../BasicRAID.html

It might be easier if you state the parts you don't understand. That said, 2,3 and 4 are rarely used, or supported. Most RAID users use RAID0, RAID1, RAID5 or a combination of RAID0 and RAID1, or JBOD.

[Digerati]

I think these two sites explain it well:

http://www.acnc.com/04_01_00.html
http://www.accs.com/.../BasicRAID.html

It might be easier if you state the parts you don't understand. That said, 2,3 and 4 are rarely used, or supported. Most RAID users use RAID0, RAID1, RAID5 or a combination of RAID0 and RAID1, or JBOD.

[SHENGTON]

Hello Digerati, good evening.

When using RAID, is it necessary to use same hard disk size?

For example: I have 80GB, do I have to pair it with 80Gb as well?

OR

I can just mix it with 160GB and so on?

[JnMrule Ent.]

This is the BEST way to find what you want. This is VERY effective no matter what you're looking for on the internet.
1) Go to your favorite search engine like
www.google.com
2) Just put exactly what you want to know in seperated by a vs.
Example:
RAID 2 vs RAID 3
You will ALWAYS get more than what you asked for. Good luck and happy computing!

[Digerati]

For true RAID, the disks normally need to be identical. For striped RAID0, you can used mixed sizes but the RAID will take on the size of the smallest drive. For JBOD, which is not really a RAID, disks of different sizes can be used to make (from the system's point of view) one big drive.

Note for

[SHENGTON]

Hello Digerati, good morning.

Your posts are very informative. It makes me easy to comprehend.

Last two questions:
1. In RAID 2 and 3, if the parity disk is damage can I still recover the files?
2. In RAID 4, if the ECC disk is damage can I still recover the files?

[Digerati]

The files are not lost so there is no recovering them. If you lose any disk, the data is still distributed across the other disks. You replace the disk, the array resyncs, and you are good to go.

Only RAID0 - striping has no redundancy. If you lose either disk, your data is gone. All other RAID types retain your data if you lose one disk. Some RAID types can suffer multiple drive loses and still retain your data. But of as can be expected, these redundant arrays suffer from overhead costs and often performance as well.