So one of my drives appeared to die and I'm going to need to replace it.  Before I even buy the new drive I want to understand what I'm walking into and what the implications of my choice are going to be.

 

My setup:  unraid 6 beta 12.

 

Parity = 2tb (can't remember if you choose a file system for parity but if you do Its xfs)

Drive 1 = 2tb in xfs

Drive 2= 2tb in xfs

Drive 3 = 2tb in xfs

 

Cache = 128 ssd

 

Drive two seems to have failed according to unraid.  I was considering buying a 3tb drive to replace it.

 

But I thought I read that the biggest drive in the array has to be your parity drive.  So of that's true what is going to happen, and what are the implications to introducing a 3tb hdd to my array?  Will it re-sort the drives and make the 3tb the new parity drive automatically for me?  Or do I need to do it manually somehow?

 

Is introducing a single 3tb a bigger headache then it's worth? Should I just get another 2tb and call it a day?

 

The only reason I was thinking of going with a 3tb is because I thought I may just make all new drives from now on 3 or 4 tb since the price is continuing to drop.  So while I'd only have one 3tb right now, when I add another drive for more space later I thought I'd go with a 3tb.

 

Lastly is there a tutorial or thread on how to properly replace a bad hdd?  Or is it really as straight forward as pulling the bad one out and pluging the new one into its spot?

 

Thanks

First, you can't replace the drive with a 3TB unit.    The parity drive MUST be >= the largest array drive.    There IS a process called "swap-disable" that's outlined in the Wiki that will let you replaced the failed drive with your old parity drive while at the same time replacing parity with a larger drive ... but it's safer to do this one step at a time.

 

Since your array is very modest in size, here's what I'd do to keep things simple and straightforward:

 

Note:  Do NOT write anything new to the array during this process => or if you do, write it to the disk shares for drives 1 or 3 ... the key is to be certain nothing else is written to drive 2.

 

(1)  Copy the entire contents of disk2 to another location ... on one of your other computers, or to an external drive.  If you don't have a backup location, this would be a good time to buy a large external drive to use for backups so you can do that.

 

(2)  Buy a new parity drive as large as the drives you want to be able to use -- 4TB, 6TB, etc.

 

(3)  Do a "New Config" -- assigning the old drive1 and drive3 as data drives; and the new larger drive as your new parity drive.  Start the array and let it do a parity sync.  When that's done, do a parity check to assure all went well.

 

(4)  Do a pre-clear on the old parity drive ... since it's been thoroughly exercised in its capacity as the parity drive, you can use the -n option so the pre-clear will be relatively quick (about 1/4th the time of a full pre-clear cycle).    When that's done, you can add it to your array and it will only require a format (very quick) instead of a full zeroing of the drive (many hours, during which the array would be unavailable).

 

 

If you don't want to use that process, the least expensive approach is the swap-disable.

 

... or (even less expensive and also "safer") buy a new 2TB drive and just replace the failed drive.

 

 

Note that the instructions in the Wiki apparently do NOT work with the latest versions of UnRAID.    Follow Thornwood's notes here:  http://lime-technology.com/forum/index.php?topic=29529.msg265090#msg265090

 

Alright thank you very much.  I'll put some thought into it.  I have the server shut down right now so nothing can be written to it until I do the replacement.

I chickened out and ordered a 2tb drive.  I didn't quite need the space and I figure when I do, I can always replace the parity drive at that time.

 

So with that said, all I have to do is shut the server down, replace the bad drive, and start the array and it'll handle the rest automatically?

I chickened out and ordered a 2tb drive.  I didn't quite need the space and I figure when I do, I can always replace the parity drive at that time.

 

So with that said, all I have to do is shut the server down, replace the bad drive, and start the array and it'll handle the rest automatically?

When you boot back up, unRAID will show the old disk as missing and won't start the array. You select the new replacement disk in the dropdown for that slot and then it will let you start the array and begin the rebuild.

... all I have to do is shut the server down, replace the bad drive, and start the array and it'll handle the rest automatically?

 

Not quite.  You start the array so it shows the old drive as missing;  THEN you stop the array, assign the new drive in place of the old one, and then start it again ... then it will do the rebuild.

 

Well, everything seems to have gone smoothly.  Thanks for the help!