3 x 250GB SATA2 Hard Drives, RAID Advice

norbie

norbie

norbie

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So I have 3 x 250GB SATA2 Hard Drives (Western Digital Raid Editions) for my new build.

What shall I do with them? I was going to go for RAID 5 but not sure now. I want to keep my data safe so I don't want to use RAID 0 for instance.

I have the Asus P5B Deluxe board so I can use RAID 0,1,5,10 I think.

Any RAID experts suggest a system for me? :)
 
norbie said:
So I have 3 x 250GB SATA2 Hard Drives (Western Digital Raid Editions) for my new build.

What shall I do with them? I was going to go for RAID 5 but not sure now. I want to keep my data safe so I don't want to use RAID 0 for instance.

I have the Asus P5B Deluxe board so I can use RAID 0,1,5,10 I think.

Any RAID experts suggest a system for me? :)
Click to expand...
I'm no expert but raid 0 will give you 500GB from 2 drives striped leaving you with one 250GB drive so i don't think you can have the third in the raid as backup as it would need to be 500GB worth as well.
If you find that this is so by your self or from others it may be a good idear to do what i have done & have the third drive not on the raid & just use it as back up with backup SW.
 
If you only have the three disks don't go with the onboard RAID5 option, the parity calculations have to be done by the main CPU which not only causes excess CPU load but reduces the write speed to around 15-20Mb/s rather than the 50-60Mb/s which you would get from a single drive. This is going to be very noticeable whenever any page file access is required.

If you don't want to use RAID0 then I'd just go with 3 individual drives and spread things about on them - put the page file on a different drive to the one you boot from for example.
 
Oops just seen above post.

I might go with RAID 0 then with 2 drives, and possibly get another to have 2 sets of RAID 0. I'm just worried about losing data. Is there any advantage from having a RAID array rather than using the drives separately within Windows?
 
Speed is the only reason for using RAID0. If you have at some of the older posts there are a lot of HDTach graphs which show the difference between single drives and RAID0 arrays.

I'd advise against running 2 sets of RAID0 unless you have a good backup strategy.
 
If you run RAID 10 you get simultaneous writes to a pair of RAID 0 arrays. RAID 10 is better than RAID 1 as the writes are independent so an error on one drive is not copied to the other as they are in RAID 1.
 
Not quite sure what you mean by that, the writes are independent for all mirrored RAID levels. Data goes from the controller to disk1 and disk2, it isn't written to disk1 and then copied to disk2. No RAID level will protect you from writing out corrupt data in the first place though.
 
Sorry -I have a bad habit of being unclear.

With RAID 1 on 4 disks the RAID 0 takes priority and the copy is made from one RAID 0 array to the other. If an error occurred in the striping process it is copied. There is no check. With RAID 10 it happens the other way around. Only validated data is striped, so there is less risk of errors on the 'copy'.

Is that clearer?
 
WJA96 said:
Is that clearer?
Click to expand...

Not really, I've never heard of a RAID controller which copies data within the array for anything other than recovery purposes. As far as I'm aware all original writes come from the controller not from the other half of the mirror.

The difference between RAID10 and RAID0+1 is that 0+1 is a mirror of stripes and 10 is stripe of mirrors therefore 0+1 cannot handle 2 failures unless they're in the same stripe whereas 10 can handle any 2 drives failing.
 
Which is what I said. If you stripe first and then mirror the error is on both arrays. If the mirror first and then stripe the error will only be on 1 array.
 
Hmm I might go for a RAID 0 of 2 disks, then keep the other one (and another 250gb I have which is only SATA1 as backups/storage for important files.
 
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