Hello there,

 

I am thinking about this for some time, and I was hoping to get some ideas from you.

I have 4 x 14 TB drives in a raidz1 pool.

 

I would like to add 4 x 14 TB to my machine and switch to raidz2.

 

For my understanding, this is what i would have to do:

 

1. Create a vdev with the new drives (raidz2)

2. Move the data over to the new vdev

3. destroy the existing one and recreate is as a raidz2

4. move the data back

 

Is that the approach that you would choose, too?

 

Am i missing/not getting something here?

 

 

In the end do you want to have one pool with 8 x 14TB with two vdevs or two 4x 14TB separate pools? Not clear to me from your description.

Since this was never resolved...i'm taking over!

Lets say i wanted the 8 x 14TB with two Vdevs setup (one raidz2 already exists that i would be adding to)?

My guess is that i would stop the array,

expand the pool from x4 to x8,

assign the x4 new (unformatted) drives,

and start the array again?

 

Beyond that, i am a bit lost...and scared!

 

UPDATE:
It seemed to work properly (using above steps), but i expected the re-silvering process to take some time, and show some drive activity (at least on the new drives) as things were balanced out to the new vdev.  It shows the additional available space (double form before), and drive activity seems to be writing to the whole pool equally!  I will assume its good; but i feel like i am missing a step, and only the original pool drives have the (old) data on them.  Can someone confirm any more steps i must take?

Additionally, if i was to want to remove one of the vdevs (assuming there is enough space on the remaining vdev), is that possible?  Or does this have to be done one disk at a time?

Edited January 9, 20251 yr by miicar
UPDATE

4 hours ago, miicar said:

My guess is that i would stop the array,

expand the pool from x4 to x8,

assign the x4 new (unformatted) drives,

and start the array again?

Correct.

 

4 hours ago, miicar said:

but i expected the re-silvering process to take some time, and show some drive activity (at least on the new drives) as things were balanced out to the new vdev. 

There's no resilvering, the nee vdev is just added to the pool, zfs doesn't do any data balance when a new vdev is added, new writes will prefer the new vdev though

9 hours ago, JorgeB said:

zfs doesn't do any data balance when a new vdev is added

so the 2 vdev's act as JBOD to each other not raid0.  good to know!

Thanks for confirming this for me!

20 minutes ago, miicar said:

so the 2 vdev's act as JBOD to each other not raid0.  good to know!

Both vdevs are stripped together, for reads and writes, but new writes will go predominantly to the new vdev, if you are on v7 you can check the data distribution by clicking on the pool, e.g., the 2nd vdev on this pool was originally smaller, and the pool was like at 95% capacity, so now that I've upgraded all the disks in that vdev, all new writes basically go only there, since the other one is almost full.