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RAID 5?

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furious5

MIS
Jan 8, 2003
103
GB
I am just about to order a new server, and have been advised to go for a RAID 5 configuration.

Now my question is if I get a RAID 5 configuration I was considering getting 3 X 36GB disks, but what total of disk space would this give me?

I know this may sound a dumb question, but I was just puzzled when thinking about how RAID 5 works.

Also can anyone point me at any decent articles that would help me in getting the server set up with a RAID 5 configuration once I have actually got the server.
 
Array Size = (Size of Smallest Drive) * (Number of Drives - 1)

Array Size = 36g * 2

72g

As for the configuring the RAID are you buying a Server or Building a Server.

If you are buying a complete server then the raid will be configured for you. Here are some links that may help with understanding Raid a little bit better.



 
The best way to remember it, if you can't remember the formula wbg34 just posted, is that RAID 5 always takes up 1 disk's worth of space for parity reasons. You do actually get storage on all 3 disks, but 1/3 of that is going to parity for fault tolerence. If you had 5 disks, 1/5 of the disk space would go for parity, etc.

Hope that helps. Catadmin - MCSA
 
Guys that is great cheers for such a quick reply.

That one really puzzled me today when I was trying to spec this server and trying to work out how much disk space we would need.

Thanks for the articles also, I will have a read over these in the next couple of days.
 
One addition to the above.
You must remember that when you format the drives you will lose some space. It is not unheard of for a "36GB" SCSI drive to format to 33GB. So you may only get about 66GB of storage after formatting.
Just giving you a heads up.
 
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