I have a 1TB Sata SSD I am currently using for my cache drive. I recently installed a 1 TB NVME drive that I want to use as the cache drive instead.

 

Ideally I would like to copy what is on the SSD over to the NVME and then just assign the NVME to the prior SSD drive slot.

I tried using file manager to copy the drive over. That worked. But then when I took the pools offline and tried to assign the NVME to the SSD slot it just responded "wrong" and would not let me restart the pool.

Since this isnt parity protected am I still required to create a new "new config" and start parity all over?

Do you also have array disks assigned? You can just recreate the pool, but a new config will also work.

yes I have array disks assigned. Why must I be forced to recalculate parity on a non parity protected drive?

If there's no parity you can't recalculate parity, you can just do a new config (Tools - New Config) and re-assign the devices as you like.

56 minutes ago, JorgeB said:

If there's no parity you can't recalculate parity, you can just do a new config (Tools - New Config) and re-assign the devices as you like.

What I am saying is if I do as you suggest the "new config" will require recalculating the parity for the array drives.

I cant swap or reassign the cache drives without creating a "new config"

Edited December 4, 20241 yr by xokia

You can skip New Config by deleting the pool, creating it again with the correct settings and assigning the new drive to it.

Sorry, misunderstood, if it's just a pool device you don't need to do a new config:

 

7 hours ago, JorgeB said:

You can just recreate the pool

 

4 hours ago, JorgeB said:

Sorry, misunderstood, if it's just a pool device you don't need to do a new config:

 

 

When I tried that it told me I was "wrong" and prevented me from starting.

 

I copied ssd cache ->nvme cache using file manager

stopped the array

unassigned the ssd cache and assigned the nvme cache to the prior SSD slot.

When I did that I get a red X and it says "wrong"

It wont let me add a different drive to a slot used by a prior drive.

 

I am way past the easy fix at this point and I created a "new config" to allow me to assign the new cache drive.

Once it complete I'll post some pictures hopefully it makes it more clear.

Edited December 4, 20241 yr by xokia

11 hours ago, xokia said:

When I tried that it told me I was "wrong" and prevented me from starting

You just recreate the pool, unassign previous pool device, start array, stop array, assign new pool device (this assumes you are on v6.12, it's a little different with v7.0.0)

On 12/5/2024 at 1:05 AM, JorgeB said:

You just recreate the pool, unassign previous pool device, start array, stop array, assign new pool device (this assumes you are on v6.12, it's a little different with v7.0.0)

I wish it would have been that easy but it would not allow me to do that. When I tried their was a big red X next to the cache drive and it stated "wrong"

 

I had to create a new config with the cache drives swapped and then recalculate parity. It all works now. I have not upgraded to 7.0 yet I'd like to hear its stable and everything works before making that jump.

Edited December 16, 20241 yr by xokia

11 hours ago, xokia said:

When I tried their was a big red X next to the cache drive and it stated "wrong"

You just need to check the "I want to do this" box next to array start button, again assuming v6.12

No way to change cache drive without rewriting parity

So this is annoying. I want to change a cache drive and I MUST recalculate parity

 

I swapped in a larger cache drive

 

Chose preserve current assignment

 

Then go to start the array

 

For those saying you can swap out the parity drive without a costly parity rebuild IDK know how you folks are accomplishing that. That information does not seem correct.

10 hours ago, xokia said:

No way to change cache drive without rewriting parity

There is, something is not correct.

11 hours ago, xokia said:

Then go to start the array

You must check the "parity is already valid" checkbox nest to array start button. 

It still says "will be overwritten" on the parity drive line but that's not actually going to happen in this case.

Edited February 18, 20251 yr by Kilrah

On 2/17/2025 at 9:07 PM, xokia said:

No way to change cache drive without rewriting parity

So this is annoying. I want to change a cache drive and I MUST recalculate parity

You can.   

 

The message about overwriting parity when formatting needs some slight rewording to make it clear it only applies to formatting a drive that is part of an Unraid parity protected array - it does not apply to formatting a pool.   It was originally introduced when the only use for a pool was as a 'cache' drive and to stop people thinking that if a drive showed as unmountable in the main array it needed formatting when instead the correct action to take was to try and recover the file system.  When formatting a pool the existing contents are simply overwritten (no matter how many drives make up the pool).

On 2/19/2025 at 1:04 AM, itimpi said:

You can.   

 

The message about overwriting parity when formatting needs some slight rewording to make it clear it only applies to formatting a drive that is part of an Unraid parity protected array - it does not apply to formatting a pool.   It was originally introduced when the only use for a pool was as a 'cache' drive and to stop people thinking that if a drive showed as unmountable in the main array it needed formatting when instead the correct action to take was to try and recover the file system.  When formatting a pool the existing contents are simply overwritten (no matter how many drives make up the pool).

This has bit me twice when swapping out a cache pool for a larger cache drive. 1.3 days to rebuild the parity. Hopefully you folks can improve this in the latest update (wether that is improved documentation or a more user friendly GUI IDK). I didn't see anyway to proceed without rebuilding the entire thing. So sucked it up and rebuilt the parity. I couldn't restart the array without agreeing to restart parity.

Can I dynamically change the cache pool size? My cache pools are NVME or SSD. I have a bunch of files I leave in the cache pool because they are lots of small files. Seek times on HDD are terrible specially for lots of small files. This has served me well but I may hit my specified size sometime in the near future.

Edited February 22, 20251 yr by xokia

56 minutes ago, xokia said:

I didn't see anyway to proceed without rebuilding the entire thing.

Mentioned it to you in my previous post.

1 hour ago, xokia said:

Can I dynamically change the cache pool size? My cache pools are NVME or SSD. I have a bunch of files I leave in the cache pool because they are lots of small files. Seek times on HDD are terrible specially for lots of small files. This has served me well but I may hit my specified size sometime in the near future.

If you have used btrfs as the file system type for your 'cache' pool then you can easily add more drives to increase the available space.    If it is already redundant (i.e. in RAID1 profile) then you can swap out individual drives one at a time for larger ones. 

11 hours ago, Kilrah said:

Mentioned it to you in my previous post.

Your post came after I rebuilt. I didnt wait around for an answer.

10 hours ago, itimpi said:

If you have used btrfs as the file system type for your 'cache' pool then you can easily add more drives to increase the available space.    If it is already redundant (i.e. in RAID1 profile) then you can swap out individual drives one at a time for larger ones. 

I am using btrfs for cache pools. I think I read somewhere that was what you wanted for SSD and NVME drives.