First off im a newbie at unraid. I got a dell R710 6 bay 2 TB 7.2 Sata.. Normally they would all go to a hardware raid controller but I found unraid and figured take it for a spin..

 

Which leads me to story and question.

 

I notice the 2 parity drives and the 30 standard drives or arrays. Yes I got the pro edition .. go big or go home right? .. (Go Magnums)

 

Before I installed unraid I put my 6 drives in a raid 6 through the hardware settings (Ctrl R) because thats what im use to from work. When I was finished and logged into unraid > Drives I saw  it detected the full raid 6 as a single entity. Which was great . I think. 30 arrays right? 360 drives+ .. etc etc (Because why not)

 

Leads to the question. Since it detected the full raid 6 does it still act as a raid 6 array with the standard raid 6 parity or as a single drive? Raid 6 by default has parity built in in normal systems. But Im wondering does it act differently in unraid?

 

Remember completely new to unraid, Please take care of me

 

Interesting that your first is so corner case...

 

What you are talking about is called plaid, nested or layer raid. The most common is raid 10, striping data over mirrored drives. But raid 50 and raid 60 are not uncommon. There are commercial products offering plain like 56 and 66, again think of systems with hundreds of drives.

 

Two problems with actually doing this with unRAID, though you can do it.

 

1) As you mentioned, the number of drives needed to do it. Since you would need at least a parity and a data drive in unraid, and in the lower controller raid, that's 4 drives, with a yield of 2xdrive size. It just multiplies up from there.

 

2) the number of controllers/slots will also be a factor. To get those 30 arrays, how many controllers will be needed, and thus slots?

 

I don't know what kind of controller is in your R710, but you'll want to get those drives switched over to JBOD so each is directly addressable from unRAID.

Thanks for the reply.

 

The controller I have is a Perc H700. It can handle the 6 disks .

 

So im changing the settings around..

 

What I did was I had all 6 drives in a raid 6 with no parity. But then I put 2 drives for parity and mounted  the remaining for as a raid 6 as data drive.

 

I thought that if I expanded the array with another controller using E SAS I could mount those drives as a second drive. and scale up that way..

 

Am I doing this right? Its odd using unraid instead of directly using the raid controller.

 

 

 

 

I would like to add the following:

 

A major selling point for unraid is the fact that when loosing multiple drives you still retain the information on the drives that are still ok.

 

In an extreme scenario with a 10 drive array and 9 drives failing you still retain the data on the one correct drive.. With traditional raid this is not the case, loose over a number of drives and you loose everything.

 

With mixing the two scenario's you are in basis loosing a large part of that unraid major selling point.

 

Also: The one reason for striping is mostly the speed benefit when writing to the array, with unraid the write penalty is on the logic that  keeps parity in sync and not in the speed of the drive.

 

Both two combined for me mean the following:

 

1) You can no benefits

2) You increase risk with multiple drive loss

3) You increase complexity in your setup leading to a more difficult time solving issues

4) You increase the number of components in your setup and therefore increasing the likelyhood of failure

 

With all of the above I am seriously interested why this would something you would want to pursue, I might be overlooking some benefit ofcourse and would like to learn from that.