Replacing all data drives but keeping Cache

[adminmat]

I need to remove all the data drives from the unRAID OS and replace with new empty drives. No rebuild is necessary. I only want to keep the cache drives and their data.

 

I'm confused on the process of doing this. Others are suggesting I use the Tools > New Config tool but there is limited information on how to use this and I feel I'm going to accidentally delete my cache drives. There are many threads where people replace one or two drives but I can't find any threads where someone is replacing all the drives and keeping the cache. No rebuild necessary.

 

Can someone please explain step by step how this is done?

 

This is what I assume now:

 

1) Connect the new data drives to be used to my motherboard.

 

2) Drives will auto mount and then give me the option to Preclear

 

3) After pre-clear there will be an option to add these drives to the array

 

4) Once added to the array I then use Tools > New Config to remove the old drives (shown in image) from the unRAID OS

 

 

Does this sound remotely correct? I'll say again. I really don't want to erase everything on my cache drives. This is why I'm being careful to go through this process.

 

 

[Frank1940]

Let me seek a bit of clarification.  You are physically discarding three 8TB drives.  If this is the case, why are you doing this?  (If I seem a bit presumptuous, please forgive me.  I simply cannot think of a reason such a course of action is a rational act...)

[adminmat]

27 minutes ago, Frank1940 said:

Let me seek a bit of clarification.  You are physically discarding three 8TB drives.  If this is the case, why are you doing this?  (If I seem a bit presumptuous, please forgive me.  I simply cannot think of a reason such a course of action is a rational act...)

 

This is exactly what I'm doing.  All three drives were fried one day for reasons I could not determine. All three drives could not mount and I can not even get SMART to initialize. I took the drives to a data recovery shop and they said these WD shucked helium drives can't be recovered. So I'm starting from scratch. Will not be using that disc enclosure or PSU again.

 

Here is my old thread on that:

 

It was mostly my archived blu-rays and my plex share. So it's just the matter of re-archiving all the disks. I did not have a backup.

 

[JorgeB]

1 hour ago, adminmat said:

2) Drives will auto mount and then give me the option to Preclear

Don't know what you mean by this, drives don't auto mount, they are just detected, also preclear is optional.

 

1 hour ago, adminmat said:

After pre-clear there will be an option to add these drives to the array

Like mentioned, preclear is optimal, drives can be assigned to the array at any time.

 

1 hour ago, adminmat said:

4) Once added to the array I then use Tools > New Config to remove the old drives (shown in image) from the unRAID OS

New config is done BEFORE adding new drives.

 

[adminmat]

31 minutes ago, JorgeB said:

Don't know what you mean by this, drives don't auto mount, they are just detected, also preclear is optional.

 

Like mentioned, preclear is optimal, drives can be assigned to the array at any time.

 

New config is done BEFORE adding new drives.

 

The instructions say "Use the 'Preserve Current Assignments' selection to populate the desired disk slots after the array has been reset."

 

What does "Reset" mean?

 

Again, my concern is not to delete the Cache drives. When i use this tool what should I select? The way the instructions are written I should only check "Cache slots" to preserve the Cache drives. And this will not erase them?

 

 

The way it is written is confusing. There are many posts on this forum and Reddit where others were confused of these instructions. 

 

[trurl]

It just means the drive assignments are reset.

[JorgeB]

Preserve assignments is just to facilitate when using the same devices, since you'll not be using any of the existing array devices no point in preserving them, you can still preserve cache (or don't and just re-assign them).

[adminmat]

5 minutes ago, JorgeB said:

Preserve assignments is just to facilitate when using the same devices, since you'll not be using any of the existing array devices no point in preserving them, you can still preserve cache (or don't and just re-assign them).

So by checking Preserve Assignments for Cache Drives it will not erase the Cache drives?

 

 

[trurl]

New Config never changes any disk contents except it (optionally and by default) builds parity on disks assigned to parity slots.

[adminmat]

Thanks for the guidance here @trurl and @JorgeB

 

Tonight I finished with the Preclear of the two new 8 TB drives. I went in Tools >  New Config and only selected to preserve the Cache Slots. When I did this it cleared out the old drives listed in array devices under the Main tab. I used the drop down menu to populate the new drives under Array Devices. One for Parity and one for Disk 1.

 

I then started the array and was prompted to enter my passphrase (I had the prior drives encrypted). I entered the passphrase and started the array and it showed this:

 

 

I started the format for Disk 1. It looks like the format only took a few minutes. Parity is showing as Invalid and shows (Parity-Sync / Data-Rebuild in progress... Completed: 3 %). Elapsed time is 11 Hours 17 Minutes. Shouldn't this be faster since I just finished the Pre-Clear of both drives?

 

It didn't give me the option to select a file system. I assume they will be xsf unencrypted now?

 

Can I now set up the shares on Disk 1 and start moving data into those shares or should I wait for the Parity to finish syncing?

 

I do see my Docker Containers, Plex, Pihole, Krusader so that's good news.

 

 

 

[trurl]

Parity sync always does the entire disk. It makes no attempt to outsmart itself by assuming anything about the state of other disks. 

 

If you don't explicitly choose the filesystem of a specific disk it is formatted with the default from Disk Settings. 

 

Using the array during parity sync will not make parity invalid but it will make things much less efficient since all disks are involved and parity sync will be accessing some parts while other activity will be accessing other parts resulting in a lot of head movement and waiting for spin to reach the sectors involved. How could I be otherwise with mechanical disks?