Two drives in RAID 0 and Two drives in RAID 1 on same system?

zank · Mar 11, 2008

I'm sorry for the newbie RAID question, but I can't seem to find the answer in the stickeys or in a search. And it may be such an easy answer that it is obvious and I just don't realize it.

If a motherboard has 4 SATA headers and RAID support, can I use two smaller drives in RAID 0 for the OS and applications and then two other drives in RAID 1 for data and files? Again, sorry if this is completely obvious.

And if this is possible, is there any advantage to this approach over RAID 0+1?

Thanks!

tuskenraider · Mar 11, 2008

Yes you can do that. The difference is that seperate RAID arrays means your RAID0 drives aren't being mirrored, but you have the space of the RAID1 to do as you please, and can put an image of the RAID0 array to store on in case of failure. RAID0+1 is using four drives with only the use of two, but has the fault tolerance of the backup drives. I'd do seperate arrays personally.

fritzman · Mar 11, 2008

What sort of motherboard (Model) is it? If it has any of the Intel Matrix Capable controllers... it might be well worth your while having a quick skim through the sticky about it.

A lot depends on whether the drives are identicle. If they are, then I would strongly recommend the Matrix... you could do a 4 x drive Raid0/Raid10 mix, but I'm getting ahead of myself.

First up... tell us about the board and the drives.

tuskenraider · Mar 11, 2008

fritzman said:
If they are, then I would strongly recommend the Matrix... you could do a 4 x drive Raid0/Raid10 mix, but I'm getting ahead of myself.

Either way, if he can afford four drives, what reasoning do have that risking 2 arrays with four points of failure(drives) is more beneficial than risking only one array with each pair of drives? Any way you look at it, Matrix RAID really is for people who must compromise their RAID setup because of drive/power/budget limitations, not because there is a superior configuration to be had.

fritzman · Mar 11, 2008

tuskenraider said:
Either way, if he can afford four drives, what reasoning do have that risking 2 arrays with four points of failure(drives) is more beneficial than risking only one array with each pair of drives? Any way you look at it, Matrix RAID really is for people who must compromise their RAID setup because of drive/power/budget limitations, not because there is a superior configuration to be had.

Maybe we're a bit OT, but the way I've set up my four... I can have any two drives die and be fully recoverable (as I understand Raid10)

tuskenraider · Mar 11, 2008

fritzman said:
Maybe we're a bit OT, but the way I've set up my four... I can have any two drives die and be fully recoverable (as I understand Raid10)

I think it's kinda relevant since you suggest it, but if you do lose 2 drives that happen to be on one side of the mirror from corruption or drive failure, you're down.

fritzman · Mar 11, 2008

tuskenraider said:
I think it's kinda relevant since you suggest it, but if you do lose 2 drives that happen to be on one side of the mirror from corruption or drive failure, you're down.

Mmmm... okay... I thought I was safer (and faster) than Raid5, but apparently not. I obviously misunderstood what Raid10 was capable of... Maybe I should revert to my 3 x drive Raid5 setup and simply run a hot spare?

So if we call the drives A1 & A2 as one Raid0 set and B1 & B2 as the mirror set... if any single drive dies, the PC carries on, using the other set until the drive is replaced.

If A1 & A2 die, B1-B2 pick up the ball and the PC continues to run as normal until A1 & A2 are replaced... this I know. (and the reverse obviously, if B1 & B2 die, etc)

Are you saying that if I lose any other combination of two drives, that I've lost the lot? because I understood that not be be the case (as it's not something I particularly want to test right at the moment), or have I still got it wrong?

noegruts · Mar 11, 2008

fritzman said:
Mmmm... okay... I thought I was safer (and faster) than Raid5, but apparently not. I obviously misunderstood what Raid10 was capable of... Maybe I should revert to my 3 x drive Raid5 setup and simply run a hot spare?

So if we call the drives A1 & A2 as one Raid0 set and B1 & B2 as the mirror set... if any single drive dies, the PC carries on, using the other set until the drive is replaced.

If A1 & A2 die, B1-B2 pick up the ball and the PC continues to run as normal until A1 & A2 are replaced... this I know. (and the reverse obviously, if B1 & B2 die, etc)

Are you saying that if I lose any other combination of two drives, that I've lost the lot? because I understood that not be be the case (as it's not something I particularly want to test right at the moment), or have I still got it wrong?

You have it right. 4-drive RAID10 is "safer" than 4-drive RAID5 in that it can tolerate one drive failure and *some* 2-drive failures whereas the RAID5 configuration can only tolerate one drive failure.

Neither one is a substitute for a backup strategy...

fritzman · Mar 11, 2008

Cheers for that.

I actually thought that is could withstand A1 & B1 or B2 going, so it would still run off the other two, but clearly that is wrong.

Need to bring out the 1Tb external again!

B

zank · Mar 11, 2008

Guys, thanks for the information so far. Here is what I have in mind for my next build.

board: XF nForce 680i LT, so I don't think the Matrix RAID is an option
CPU: Core 2 Quad Q6600 2.4
RAM: OCZ SLI-Ready Dual Channel 4096MB PC6400
RAID 0 drives: Seagate Barracuda 7200.10 80 GB
RAID 1 drives: Seagate Barracuda 7200.10 320 GB

Do you think there is a speed advantage to doing two different arrays (80 GB RAID 0 and 320 GB RAID 1) as opposed to a 0+1 with 4 identical drives?

Two drives in RAID 0 and Two drives in RAID 1 on same system?

zank

New Member

tuskenraider

Senior Member

fritzman

Member

tuskenraider

Senior Member

fritzman

Member

tuskenraider

Senior Member

fritzman

Member

noegruts

Member

fritzman

Member

zank

New Member

Similar threads