Transitioning to new drives with a broken drive

[coptician]

Hey all,

 

I noticed last week that one of my drives was dying, so I ordered 4 new drives to replace all of them.

 

I am going to switch from:

 

4x4TB (one parity)

 

to:

 

4x8TB (one parity)

Potentially adding 2x4TB to that.

 

I thought I understood what to do, so yesterday I installed a new drive to act as parity. It's currently the second parity drive.

 

During the rebuild, the 4TB drive errored out, so now I am in a strange state where I have a 4TB parity, an 8TB parity, 2 working 4TB drives and a broken 4TB drive.

 

I added another 8TB drive to serve for data, but I can't add it to the pool because of the 4TB parity drive. (I can add the other 2 8TB drives when needed)

 

How should I proceed from here to get the data transferred over to the 8TB drives?

[trurl]

Read this and come back with any questions:

 

https://wiki.unraid.net/The_parity_swap_procedure

[trurl]

Also, go to Tools - Diagnostics and attach the complete Diagnostics ZIP file to your NEXT post in this thread.

[coptician]

Thanks!

 

I've attached the file.

 

So what I'm gathering here is that adding the new 8TB parity drive was not the right procedure, and it'll need to calculate parity again.

 

The way I understand it, I'm essentially turning the 4TB parity into a 4TB data drive this way, at least in terms of assignments. Is that right?

 

bifrost-diagnostics-20200825-1709.zip

[trurl]

After looking at those diagnostics I realized I didn't look closely enough at your screenshot. You can't add a disk larger than parity, and you shouldn't attempt to add a disk when you have a disabled disk anyway.

 

Unassign that new disk and see if you can start the array. Then post a new screenshot and new diagnostics.

[coptician]

Do you want me to start the array without either of the 8TB drives, or only without the 8TB data drive?

[trurl]

The 8TB parity2 is OK. Just unassign the 8TB data drive since you can't have any data disk larger than any parity disk.

[coptician]

Here you go.

bifrost-diagnostics-20200825-1747.zip

[trurl]

Yes, that disk2 definitely needs replacing:

Serial Number:    Z304EEQX

ID# ATTRIBUTE_NAME          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE
  5 Reallocated_Sector_Ct   PO--CK   096   096   010    -    4680
187 Reported_Uncorrect      -O--CK   001   001   000    -    109
197 Current_Pending_Sector  -O--C-   092   092   000    -    1408
198 Offline_Uncorrectable   ----C-   092   092   000    -    1408

You should have been seeing warnings for that disk on the Dashboard, and also getting Notifications for it. You should set up Notifications to alert you by email or other agent as soon as a problem is detected. And you should deal with problems as soon as they arise and not let them turn in to multiple problems and data loss.

 

Do any of your other disks display SMART warnings on the Dashboard page? I did notice a few CRC (connection) errors on disk3. You can acknowledge those by clicking on the warning and it will warn again if they increase. Parity also has a few Uncorrected but you are replacing that next anyway.

 

Since you have dual parity, it is OK to run with that disabled disk2 while you upgrade parity1.

 

Assign a new 8TB disk to parity1 slot (the disk already installed or another if you prefer) and let it rebuild.

 

Be very careful when mucking about in the case. Disturbing connections is by far the most frequent cause of problems with rebuilds/replacements.

[coptician]

Yeah, I did get warnings about that disk, but unfortunately it took a few days for the new drives to get here.

 

Okay, so I am going to take parity 1 ouf of the pool, create a new parity 1 with the 8TB drive, and letting it rebuild based on that. Then I can reassign current parity 2 into a data drive and transfer data over to that.

 

That makes sense to me. Thanks, I'll get to work on that!

 

Edit: The other drives are all showing healthy, so we should be alright.

 

Edited August 25, 2020 by coptician

[trurl]

1 hour ago, coptician said:

I am going to switch from:

 

4x4TB (one parity)

 

to:

 

4x8TB (one parity)

Potentially adding 2x4TB to that.

If you plan to end up with 4x8 plus 2x4, then the way to do that is to keep those 2x4 good disks (disk1,3) as they are. After rebuilding parity1 onto 8TB, remove parity2 and use that disk to rebuild disk2. Then you can add other 8TB to new slots.

 

Regardless, there isn't any need to transfer files from one disk to another. The whole point of parity is to allow you to rebuild the contents of a disk to a new disk. No need to move files around or empty drives so you can replace them, etc.

 

Let me know if you need more on how to get to your desired result. Moving files around should not be necessary.

 

[coptician]

Thanks! It's going to take a day to parity sync so I'll check in then if I'm unsure. But I think I get it now, so thank you!