Convert partial pool topology without rebuild?

[avggeek]

Hi folks,

Prior to switching to TrueNAS Scale, I was running a Ubuntu Server LTS install with a ZFS pool. When I first started, I could not afford to buy sufficient capacity to create a RAID-Z2 pool and instead created a RAID-Z1 pool. When I managed to upgrade the capacity, I continued with a 2nd RAID-Z1 VDEV.

Thereafter, I moved to TrueNAS SCALE and also moved to new hardware that supports up to 24 drives. So I installed 6 drives at one go and probably incorrectly, added yet another VDEV to the same ZFS pool, this time in RAID-Z2 format. So my pool now looks like this:

Code:

      rust-storage                              ONLINE       0     0     0
          raidz1-0                                ONLINE       0     0     0
            7eb6215e-27ba-ac46-a5a6-30694513e2e1  ONLINE       0     0     0
            5de37400-cf34-3143-a0e8-fe69ae0a2851  ONLINE       0     0     0
            6b783e07-b01d-3246-8244-4f0e47f15ecb  ONLINE       0     0     0
          raidz1-1                                ONLINE       0     0     0
            f20a18fe-4242-3847-9b00-eacca6784607  ONLINE       0     0     0
            aac5410c-af16-0d43-a563-705216c97a09  ONLINE       0     0     0
            153c5c1b-d50b-f343-a920-9662a1d998aa  ONLINE       0     0     0
          raidz1-2                                ONLINE       0     0     0
            a4f32912-c02d-4286-992f-8d7852b47804  ONLINE       0     0     0
            37568b59-1872-4212-8e0a-ca6a4aaa3112  ONLINE       0     0     0
            5928070e-25ae-491a-92b9-cd19d60ba8d0  ONLINE       0     0     0
            a2a45676-12cd-4046-bac8-2d5cd6492ab5  ONLINE       0     0     0
            8b03c989-3902-437f-be68-00b19d4dd1f9  ONLINE       0     0     0
            a6d9ed5c-1fd1-4baf-b757-85026c47bfec  ONLINE       0     0     0

.

I realize now that the pool is still at risk from single drive failure since there are two RAID-Z1 VDEV's and the loss of two drives in one of these VDEVs would effectively brick my pool. I'd like to figure out if there is a way for me to remove these RAID-Z1 VDEV's and create a single RAID-Z2 VDEV from these drives but without having to recreate the entire pool from scratch.

The pool is very lightly loaded (capacity wise) and I still have another 12 bays available in the server chassis so I could probably add a brand new pool and do a ZFS send|receive if that's my only option. But I'd like to figure out if there's a way to rebuild the pool without starting afresh.

Any advice is very welcome!

 

[danb35]

added yet another VDEV to the same ZFS pool, this time in RAID-Z2 format.

No, you didn't. You added a six-disk RAIDZ1 vdev to your pool. Your pool now consists of two three-disk RAIDZ1 vdevs and one six-disk RAIDZ1 vdev, all striped together.

I'd like to figure out if there is a way for me to remove these RAID-Z1 VDEV's and create a single RAID-Z2 VDEV from these drives but without having to recreate the entire pool from scratch.

Unfortunately, no.

 

[avggeek]

No, you didn't. You added a six-disk RAIDZ1 vdev to your pool. Your pool now consists of two three-disk RAIDZ1 vdevs and one six-disk RAIDZ1 vdev, all striped together.

Ah shoot. I knew I would regret adding that 3rd VDEV but I was really keen to consolidate all of my data back as I had a fair bit of data sitting in my backup Synology (not as backup but the actual data!)

Unfortunately, no.

Fair enough, thankfully I'm able to create a new pool with sufficient capacity to hold the data while I recreate the pool "the right way". Need to plan on getting the new drives installed.