Random Raid Question

[newgeneral10]

Just had a random question...  Would it be possible to have two 1TB drives in raid 0, and have both of those drives mirrored onto a 2TB drive?  That would make it Raid 10 on 3 drives, but is it possible.  The only problem I can foresee is that the two 1TB drives would be too fast for the the 2TB but I'm still curios for y'all's opinion.

[scottyseng]

5 minutes ago, newgeneral10 said:

Just had a random question...  Would it be possible to have two 1TB drives in raid 0, and have both of those drives mirrored onto a 2TB drive?  That would make it Raid 10 on 3 drives, but is it possible.  The only problem I can foresee is that the two 1TB drives would be too fast for the the 2TB but I'm still curios for y'all's opinion.

No. RAID wants the drives to be all the same size. RAID10 needs four drives minimum. RAID will cripple any larger drives to the size of the smallest drive in that array.

 

Your best bet would be to make a normal RAID1 array with the two 1TB drives and have a software backup this drive to the 2TB drive (No RAID).

[fjdhdhcyfhf]

it is possible on linux but would not achieve anything. RAID 1 with a slow and fast drive goes at the speed of the slow drive. just use the raid0 drives and use something like bacula to do daily backups

[tt2468]

You could theoretically do a raid0 in hardware raid, then use software raid for the raid1.

[dalekphalm]

14 hours ago, newgeneral10 said:

Just had a random question...  Would it be possible to have two 1TB drives in raid 0, and have both of those drives mirrored onto a 2TB drive?  That would make it Raid 10 on 3 drives, but is it possible.  The only problem I can foresee is that the two 1TB drives would be too fast for the the 2TB but I'm still curios for y'all's opinion.

Yes - but not with hardware RAID. You'd need to use a software/RAID system that allows nested RAID arrays. Such examples are ZFS with vdevs, or something like SnapRAID/FlexRAID, etc.

 

Basically, you'd "span" the two 1TB drives into a virtual 2TB drive. Then you'd mirror that virtual 2TB drive to a physical 2TB drive.

http://www.flexraid.com/

 

Depending on how the exact system works, you might have performance issues, but I don't think that would really be a huge concern.

 

It's not ideal, however, since there are a bigger number of potential failure points with a setup like this. But it can be done.

 

EDIT: Also this would not make it "RAID 10 on 3 drives". This would make it "RAID1 but with virtual drives".

[dalekphalm]

13 hours ago, tt2468 said:

You could theoretically do a raid0 in hardware raid, then use software raid for the raid1.

That would be a bad idea. Do it all in Software RAID, or don't do it at all. Hell, mixing hardware RAID and software RAID at all is a bad idea.

[newgeneral10]

6 hours ago, dalekphalm said:

That would be a bad idea. Do it all in Software RAID, or don't do it at all. Hell, mixing hardware RAID and software RAID at all is a bad idea.

I don't think any part of this would be a good idea.  I was just asking if it was possible.  I don't think anyone in their right mind would do this, other than for the giggles.

[dalekphalm]

16 hours ago, newgeneral10 said:

I don't think any part of this would be a good idea.  I was just asking if it was possible.  I don't think anyone in their right mind would do this, other than for the giggles.

You'd be surprised. We see people wanting to do inadvisable things all the time here on the forums, because they get in their head that this is the way they want to do it.

 

I'm glad you understand it's not a good idea though