Greets!

 

Can I replace a failed 2TB data drive with a 3TB one?

If so, do I need to pre-clear it first or just let it rebuild?

 

Thanks!

you can use a bigger drive. but if you use a 3TB drive, your parity needs to be at least 3TB, too. and to use 3TB drive, you need unraid v5. v4.7 doesn't support disks larger than 2TB.

 

i would pre-clear the drive, simply to make sure, the drive is ok. but as alway, it's optional.

Yes you can, this is one of the great things of unraid.

 

If you put in the drive your failed data will be recreated on the new drive, when it is finished you will have all your data back and 1 TB of free room also.

 

For 3TB drives you need to be on unraid V5 though.

 

About preclear:

 

Preclear is never -technically- necessary, you can add drives without preclearing at all times. Issue is that running preclear will make sure you "catch" bad disks before you fill them with data.

 

This is why I make it a practice to allways have a spare drive, precleared and ready to go, sitting in my system.

 

If you are in a situation where you need to replace a failed drive and have no precleared one ready then you need to make a decission:

 

Option 1: Do a preclear, your will have a disk with higher chance of no failure but the time you will take to preclear your system will not be protected against data loss (you allready had one drive fail and if another drive failes parity can no longer help you, in that case you will loose data on both failed drives.

 

Option 2: Do not do a preclear, you will be protected against failure again in a short time (the time for the rebuild) BUT you might experience drive faile again shortly if the new drive is a bad one..

 

You need to make that call based on the importance of your data, I would however really advice to get a new drive quite quickly and have it handy, that is the best choice, it is also is not really "expensive", since another disk absolutely WILL fail in the future (all drives will) you are only making the investment a bit sooner.

Sorry guys, should have mentioned in the original post that I DO have a 3TB parity drive, and I'm running v5.

Will it take the array offline while it rebuilds (without pre-clear) ?

 

Km.

It will not take the array off line. But it will have to go through the rebuild cycle with all the disks working for about 12 hours give or take. The array only goes offline when a new disk is added if it's not precleared.

 

The preclear doesn't give you any advantage when doing a rebuild. You run it if you want to do a new drive burn-in or pre-test before using the drive.

 

Sounds like a plan! I put in the drive and set the array to rebuild and expand.

Now it shows the new drive, but the line looks like this:

 

Disk 11 WDC_WD30EZRX-00MMMB0_ (sdh) 2147483596 27 °C 2.20 TB

 

only 2.2 TB? Or is that because it has to do the rebuild first and then expands it?

 

Km

Odd, does your SATA chipset support 3T drives?

I thought it did, since my 3TB parity shows up as 3TB.

Maybe my PCIe controllers don't see 3 TB drives.... hmmm

 

I think, what I should do is stop the data rebuild, since it's going to be 2.20 TB and re-assign the drive to an onboard controller.

OR, since I have the failed drive Advanced RMAed (they will send new drive ahead) I can just use the 2TB in that position.

 

If I stop the process now, can I re-assign the drive still? Thoughts?

 

Km.

Unfortunately, you can only replace a slot with an identical or larger drive, so now that the slot shows a 2.2TB, it's stuck at that size or larger. The only way to get it back is if you backed up your super.dat file on your flash drive before you assigned the new drive.

but since a slot is not equal to the disk controller, you could switch off, connect the drive to the other disk-controller, and start up again. unraid will still use the same "slot" for that disk.

 

i'm not exactly sure, if it's save to cancel a rebuild. so someone with more experience should answer that.

but since a slot is not equal to the disk controller, you could switch off, connect the drive to the other disk-controller, and start up again. unraid will still use the same "slot" for that disk.

That is exactly what I would recommend. Cancelling a rebuild in progress shouldn't hurt anything.

I think we're good to go now!!!

 

I swapped the controller positions of two drives to put the 3TB drive on the onboard slot and here's the new read out:

 

Disk 11 WDC_WD30EZRX-00MMMB0_ (sdb) 2930266532 30 °C 3 TB

 

So it looks like we're good to go, thanks for helping me through this! Now to find some cheap PCIe controllers that support > 2TB drives! HAHAHA!

 

Cheers and thanks again for the moral support!