Failing drive: Replace, and Upgrade Parity Drive order of operations - sanity check

[axeman]

My array has 24 drives, and one of the older ones is failing - we've had a couple of read errors on it, and basically it's aged out (10+ years old)... 

 

I have dual parity (two 8tb drives). I have a somewhat faster (7200rmp, vs 5400) 8tb drive that I got a couple of weeks ago. 

 

Ideally, I'd like to replace one of the parity drives with the faster drive. I get that the speed may not be faster, esp since the other drive isn't matched. However, figured next drive I get would be a 7200 to replace the other parity drive. 

 

Then, I'd like to use the old parity drive to replace the failing drive. 

 

How do I go about doing this? 

 

1. Replace Parity Drive say Parity 1 with new drive, let parity rebuild.

2. Preclear the old parity drive

3. For replacing, follow [https://wiki.unraid.net/Replacing_a_Data_Drive] steps...?

 

Anything I'm missing? 

[itimpi]

You could use the Parity Swap procedure, but in this case that seems directly equivalent to just doing step 1) and then step 3) so you could just go with the simpler approach you outlined.

 

Any reason you want to run a pre-clear on the old parity drive?   The rebuild overwrites every sector on the drive so it’s current contents are irrelevant.   The only reason for doing this would be as a stress test of the drive but since you have already been successfully using it as a parity drive this seems unnecessary, and just takes time and puts extra wear on the drive.

[axeman]

1 hour ago, itimpi said:

You could use the Parity Swap procedure, but in this case that seems directly equivalent to just doing step 1) and then step 3) so you could just go with the simpler approach you outlined.

 

Any reason you want to run a pre-clear on the old parity drive?   The rebuild overwrites every sector on the drive so it’s current contents are irrelevant.   The only reason for doing this would be as a stress test of the drive but since you have already been successfully using it as a parity drive this seems unnecessary, and just takes time and puts extra wear on the drive.

 

Thanks. I thought we needed to do this prior to adding it to the array. If I don't need to do that, I will skip it. Save time, AND wear and tear, sign me up!

[itimpi]

3 hours ago, axeman said:

 

Thanks. I thought we needed to do this prior to adding it to the array. If I don't need to do that, I will skip it. Save time, AND wear and tear, sign me up!

Pre-clear is NEVER a requirement.   Prior to adding it to a new slot in the array it can make some sense as it avoids Unraid having to first clear it (toavoid invalidating parity) before it becomes available to start using it.    If you are doing a drive replacement or doing anything with a parity drive then it is completely optional.

[axeman]

Oh NO. 

 

I'm stuck! at step three - i noticed the entire array shows unencrypted/unlocked. 

 

Replacing the parity drive should NOT have decrypted the array, right? 

[trurl]

attach diagnostics to your NEXT post in this thread

[axeman]

1 hour ago, trurl said:

attach diagnostics to your NEXT post in this thread

I should add that the unencrypted is occurring on the drive switch. Just double checked to confirm - if I restored the existing drive - the array is encrypted and expects the key. 

[axeman]

I guess it's just misleading in the UI. I just started the array - it prompted me for key.