(Solved) Plan to replace parity and remove disks - help?

[KptnKMan]

Hi everyone,

 

Firstly, apologies for the verbosity here, I want to get this correct.

I'm looking for some advice as I'd like to make sure I've got this right, and would not like to mess up my array (again).

 

In my system I have:

- 1x 1TB cache

- 2x 6TB parity disks (new in 2019)

- 2x 6TB array disks (new in 2019)

- 4x 3TB array disks (carried over from my old server)

- a few extra Unassigned Disks

 

I've currently got a couple of things happening:

- 1 of the old 3TB drives in my array has recently started to show errors.

- 2x new 8TB WD Red drives are arriving today for my main unRAID system, ordered to replace and upgrade.

 

So I'd like to (I think this is probably the correct order to do things):

- Remove that faulty 3TB array disk, not replace with anything (effectively shrink).

- Swap in 2x 8TB disks as my parity, replacing the 2x 6TB disks there now.

- Swap in 2x 6TB current-parity disks into my array, replacing 2 of the 3TB disks.

 

I've read up this article on removing disks and shrinking arrays: https://wiki.unraid.net/Shrink_array

There seem to be a few options here, one of them including "Remove Drives Then Rebuild Parity".

This seems interesting as I would preferably not like to rebuild parity twice, if possible.

 

I'd like to find out:

- Would it be possible to remove the 3TB disk, and replace the parity disks at the same time in step 7?

- Once everything is running, can I just copy the contents from the removed disk as an Unassigned Disk, on top of the newly mounted array?

- After that, once everything settles (parity and data copied in), I would only be left with swapping in the 2x 6TB disks as normal?

 

Thanks for any advice.

Edited March 25, 2020 by KptnKMan

[KptnKMan]

My new drives arrived (yay!).

Really hoping someone has some time to maybe point me in the right direction?

Am I making any mistakes here?

[JorgeB]

22 hours ago, KptnKMan said:

Would it be possible to remove the 3TB disk, and replace the parity disks at the same time in step 7?

Yes, you can re-sync with the new parity drives, array will be unprotected during the sync, but it will be the same if you re-sync to the older parity drives.

 

22 hours ago, KptnKMan said:

Once everything is running, can I just copy the contents from the removed disk as an Unassigned Disk, on top of the newly mounted array?

Yes, assuming the disk is still working/healthy, obviously any read errors will result in lost data.

 

23 hours ago, KptnKMan said:

- After that, once everything settles (parity and data copied in), I would only be left with swapping in the 2x 6TB disks as normal?

Yes.

 

[KptnKMan]

Thanks, this is great to know I'm looking at this correctly.

 

Gonna start with this and see how I get on. 

 

Edit: I'll report back my results. 

Edited March 3, 2020 by KptnKMan

[KptnKMan]

Looks like everything went well.

Everything has been reassigned, and I removed the disks in Step 7, and swapped in the new 2x 8TB parity disks.

 

I checked all my drive logs before beginning, and saw that one of my other 3TB disks is having some strange log errors, but not write errors.

Decided to remove that disk at the same time as the erroneous drive, but means that I wont have the free space to copy everything in.

 

At least this way I will have all new drives and the same capacity, in the end.

 

So it looks like once the parity is finished rebuilding, I'll need to swap the 2x 6TB disks in before copying my data back in.

[KptnKMan]

Thanks again for the assistance, looks like the parity rebuild went without issues on the new drives.

 

Today, decided I would swap in the (previously parity) 2x 6TB drives to replace the (remaining) 2x 3TB drives.

 

I wanted to test my hotswap capabilities so I did this without restarting.

I also wanted to use the double parity to rebuild both drives at once, reducing TTL.

 

A few things, for others who might want to try this:

- Stopped the array

- Pulled 2x 3TB drives (#3 and #4)

- Insterted first 6TB disk (replacing #3), and waited a few minutes for drive to come online

- Checked UI, confirmed 6TB disk, and assigned to #3

- Insterted second 6TB disk (replacing #4), and waited a few minutes for drive to come online

- Checked UI, confirmed 6TB disk, and assigned to #4

- Started the array

 

Looks like things are rebuilding properly:

 

Looks like things are rebuilding, and my data is still accessible while its emulated. Great.

[KptnKMan]

I have a couple questions that I'm unsure about at the moment, reading the FAQ and googling doesnt seem to have shown anything up.

 

So I'm ready to copy my data from my (erroneous) 2x 3TB into my array, but I'm wondering the best way to do so.

I have about 2.2TB of data from the 2x 3TB disks, and my array looks like this:

 

- Do I simply copy the data over the share /mnt/users/X and let unRAID deal with where to put the data?

- Do I copy the data into one of the /mnt/diskX areas? Like the respective 3TB disks into /mnt/disk3 and /mnt/disk4?

- Do I need to wait until the current reconstruction is complete before beginning copying data back in?

 

 

 

[JorgeB]

9 minutes ago, KptnKMan said:

- Do I simply copy the data over the share /mnt/users/X and let unRAID deal with where to put the data?

- Do I copy the data into one of the /mnt/diskX areas? Like the respective 3TB disks into /mnt/disk3 and /mnt/disk4?

Either way works, whatever you prefer.

 

9 minutes ago, KptnKMan said:

- Do I need to wait until the current reconstruction is complete before beginning copying data back in?

Don't need to, but should, or performance for both things will be very affected.

[KptnKMan]

That's good to know.

Thanks @johnnie.black

 

I was thinking I might start the copy job and it'll be done by the time I wake up tomorrow.

[KptnKMan]

Thanks @johnnie.black for your help.

Late reply to this, but I got everything copied over. Copied everything directly onto the disks, rather than to the shares.

 

Marking this one as solved.