rebuilding and reusing drives with data

so I had some issues (and some spare cash) so I decided to upgrade my config.  I've done the following:

1) bought three new 4TB drives,

2) downed my array and disconnected the existing drives

3) added the three new 4tb drives,

4) precleared the new drives,

5) added the new drives to the array (one as the parity drive).

So I now have 8tb of storage.  I would like to add back my old data drives.  Do I

a) have to mount them somewhere else & copy the data to the new array, or

b) add them back to the array?

If a), how do I mount them?  within unraid & use MC to copy or under win7 & copy?

If b), do I have to do anything special or will unRaid see the previously used unRaid drive and just build parity & balance out the storage usage all by itself?

The only guide I've been able to find that talks about drives with data assumed the data is from win7 or some other non-unRaid OS.

Thanks in advance.

It sounds like you did a "New Config" -- is that correct?

If so, then your new array has 8TB of space but NO data on it at the moment ... right?

Assuming that's the case, you have several options ...

(1)  If you want these drive IN ADDITION TO your original drives; then shut down; reconnect the original drives; boot to UnRAID; Stop the array; and do a "New Config" => include ALL of the drives you want in the new configuration (old ones and new ones), and be CERTAIN you assign the correct drive as parity.    Then Start the array, and it will do a new parity sync.  When it's done, do a parity check to confirm all went well.  Done 

(2)  If you only want the DATA from the original drives; then I would simply connect the old data drives (one-at-a-time) to a PC via a USB bridge device [e.g. http://www.newegg.com/Product/Product.aspx?Item=N82E16812232002 ];  load the free Linux Reader [ http://www.diskinternals.com/linux-reader/ ]; and then copy all the data to your new array.

(3)  You can also do the copy from the old drives locally by mounting the drives OUTSIDE of UnRAID with Snap, but I don't use that so can't provide specific directions on its use (I prefer to do all my data copying from my main PC and just use UnRAID as a pure NAS).

...

(1)  If you want these drive IN ADDITION TO your original drives; then shut down; reconnect the original drives; boot to UnRAID; Stop the array; and do a "New Config" => include ALL of the drives you want in the new configuration (old ones and new ones), and be CERTAIN you assign the correct drive as parity.    Then Start the array, and it will do a new parity sync.  When it's done, do a parity check to confirm all went well.  Done 

...

This is exactly my situation.  I want the new drives and the old ones in the new configuration.  I'm still slightly paranoid about data loss so I'm going to try this with one of my old drives first.  If it works I'll add the other old drives and do it again.

Thanks for this.

There's no reason to do it one-at-a-time.  If you're concerned, do a "New Config" with one of the old drives and all the new ones but DO NOT assign a parity drive.    This will save you the many hours it takes to do the parity sync.

Then, when you see that it works okay, just repeat it with ALL of the drives (but, again, do NOT assign a parity drive) ... and you'll see that all of your data is there with no problem.

NOW Stop the array and assign the parity drive ... and let it do the parity sync -- and you'll then have a fault-tolerant array again with all of your data.

Be sure to do a parity check after the parity sync completes, just to confirm all went well.

Note:  I suspect your "paranoia" is due to the fact that adding new drives to an array requires that these drives be cleared first.  That is ONLY true when you're adding them to a parity-protected array -- they have to be cleared so the integrity of the parity drive can be maintained when adding the drive.    If you don't have a parity drive, you can simply add additional drives with data and all will be well.  But I didn't even suggest doing that -- the absolutely safest way to add drives with data already on them is to simply do an entirely "New Config" and include the drives you want in that configuration.  That ensure you don't accidentally try to add them to a parity-protected array (which would, in fact, cause them to be cleared).

I'm about to do a bit like the OP, mut I'm just removing drives from the array.

So the thing about correct drives is just that I include the drives I want. The order of the disks would not matter as it is a NEW config and I would not need to leave any empty slot in between the disks or anything like that?

Parity is calculated solely based on the data drives that I pick for the new array config?

the process above worked for me.  I put in the new drives & the old drives; hit NEW CONFIG; then rebuilt the parity.  The only thing that didn't work automatically was a rebalancing of the drives.  I waited for the parity to finish so I had protection and then used the console & MC to move data from my old drives to the new 4tb drives. Last think I did was add my old parity drive to the array as a data drive.

Not sure if this answers your specific questions.

I don't need to rebalance. I just want to remove 8 drives at once.

Oh, so that's entirely unlike what I did.  All of my drives with data went back into the array plus some new ones.

Are you removing empty drives or are you expecting data to be rebuilt based on the existing parity?

I'm trying to shrink the array so I can get one of the SAS cards for my other build 

And yes, removing only empty drives.

I remember that the drives that are unassigned should also be removed? But could it be done without, so I could get to the hardware config after the parity rebuild?

Note:  I suspect your "paranoia" is due to the fact that adding new drives to an array requires that these drives be cleared first.  That is ONLY true when you're adding them to a parity-protected array -- they have to be cleared so the integrity of the parity drive can be maintained when adding the drive.    If you don't have a parity drive, you can simply add additional drives with data and all will be well.  But I didn't even suggest doing that -- the absolutely safest way to add drives with data already on them is to simply do an entirely "New Config" and include the drives you want in that configuration.  That ensure you don't accidentally try to add them to a parity-protected array (which would, in fact, cause them to be cleared).

Not sure if this is true or not. I was doing something a bit unusual. My parity drive is actually a logical drive off of a RAID controller. I needed to recreate it to change the block size which would make me rebuild parity. But unRaid would see it as the exact same disk.

I also had copied a 2T drive to my new 4T drive and want to remove the 2T drive for desktop use and put the 4T drive in its place.

So I stopped the array, unassigned the parity slot, then started the array. UnRaid warned I was loosing parity as it should. Array starts - poof no parity. Then I stopped the array and tried to exchange the 2T with the 4T. No dice. Too many wrong disks. Array would not start. Had to do a new config and reassign every bloody disk. I would think that with no parity you could do anything you wanted with the drive slots  but not so. This leads me to believe that trying to add a disk to an unprotected array would zero the drive. Not 100% sure but that's my guess.

Note:  I suspect your "paranoia" is due to the fact that adding new drives to an array requires that these drives be cleared first.  That is ONLY true when you're adding them to a parity-protected array -- they have to be cleared so the integrity of the parity drive can be maintained when adding the drive.    If you don't have a parity drive, you can simply add additional drives with data and all will be well.  But I didn't even suggest doing that -- the absolutely safest way to add drives with data already on them is to simply do an entirely "New Config" and include the drives you want in that configuration.  That ensure you don't accidentally try to add them to a parity-protected array (which would, in fact, cause them to be cleared).

 

Not sure if this is true or not. I was doing something a bit unusual. My parity drive is actually a logical drive off of a RAID controller. I needed to recreate it to change the block size which would make me rebuild parity. But unRaid would see it as the exact same disk.

 

I also had copied a 2T drive to my new 4T drive and want to remove the 2T drive for desktop use and put the 4T drive in its place.

 

So I stopped the array, unassigned the parity slot, then started the array. UnRaid warned I was loosing parity as it should. Array starts - poof no parity. Then I stopped the array and tried to exchange the 2T with the 4T. No dice. Too many wrong disks. Array would not start. Had to do a new config and reassign every bloody disk. I would think that with no parity you could do anything you wanted with the drive slots  but not so. This leads me to believe that trying to add a disk to an unprotected array would zero the drive. Not 100% sure but that's my guess.

In this example, the array had a parity drive but it was missing. Arrays with no parity drive defined, as is the case once you select "New Config", allow the addition or removal of drives at will with no clearing required. Why would you set a new config to swap a drive? Rebuilding on the new drive is safer and allows more recovery options if something goes wrong.