eselarm

OK, as I thought, not enough 'headroom'
 
rock5b:/local/ssdata/nocow # btrfs inspect-internal list-chunks 2 btrfs inspect-internal list-chunks 2 Devid PNumber Type/profile PStart Length PEnd LNumber LStart Usage% ----- ------- ----------------- -------- --------- -------- ------- -------- ------ 1 1 System/single 1.00MiB 4.00MiB 5.00MiB 4 2.30GiB 0.39 1 2 Metadata/single 5.00MiB 8.00MiB 13.00MiB 1 5.00MiB 35.74 1 3 Data/single 13.00MiB 8.00MiB 21.00MiB 2 13.00MiB 100.00 1 4 Data/single 21.00MiB 1.00GiB 1.02GiB 3 21.00MiB 53.20 1 5 Metadata/single 1.02GiB 208.00MiB 1.22GiB 5 2.31GiB 23.51 1 6 Data/single 1.22GiB 512.00MiB 1.72GiB 6 2.51GiB 84.35 1 7 Data/single 1.72GiB 512.00MiB 2.22GiB 7 3.01GiB 86.48 1 8 Metadata/single 2.22GiB 256.00MiB 2.47GiB 8 3.51GiB 33.67 1 9 Metadata/single 2.47GiB 256.00MiB 2.72GiB 9 3.76GiB 14.43 1 10 Data/single 2.72GiB 1.00GiB 3.72GiB 10 4.01GiB 83.88 1 11 Data/single 3.72GiB 1.00GiB 4.72GiB 11 5.01GiB 97.23 1 12 Data/single 4.72GiB 1.00GiB 5.72GiB 12 6.01GiB 55.02 1 13 Data/single 5.72GiB 1.00GiB 6.72GiB 13 7.01GiB 85.21 1 14 Data/single 6.72GiB 1.00GiB 7.72GiB 14 8.01GiB 58.04 1 15 Data/single 7.72GiB 1.00GiB 8.72GiB 15 9.01GiB 82.03 1 16 Data/single 8.72GiB 1.00GiB 9.72GiB 16 10.01GiB 28.15 1 17 Metadata/single 9.72GiB 256.00MiB 9.97GiB 17 11.01GiB 10.30 1 18 Data/single 9.97GiB 1.00GiB 10.97GiB 18 11.26GiB 99.83 1 19 Metadata/single 10.97GiB 256.00MiB 11.22GiB 19 12.26GiB 0.58 1 20 Metadata/single 11.22GiB 256.00MiB 11.47GiB 20 12.51GiB 5.22 1 21 Metadata/single 11.47GiB 256.00MiB 11.72GiB 21 12.76GiB 0.49 1 22 Metadata/single 11.72GiB 256.00MiB 11.97GiB 22 13.01GiB 0.27 1 23 Metadata/single 11.97GiB 27.00MiB 12.00GiB 23 13.26GiB 0.06 Then doing various balance actions, then again replace action, see result below:
[334356.515225] [ T207531] BTRFS info (device loop0p2): balance: start -mlimit=3 -slimit=3 [334356.516261] [ T207531] BTRFS info (device loop0p2): relocating block group 14236516352 flags metadata [334356.608520] [ T207531] BTRFS info (device loop0p2): found 1 extents, stage: move data extents [334356.655369] [ T207531] BTRFS info (device loop0p2): relocating block group 13968080896 flags metadata [334356.882397] [ T207531] BTRFS info (device loop0p2): found 44 extents, stage: move data extents [334356.974962] [ T207531] BTRFS info (device loop0p2): relocating block group 13699645440 flags metadata [334357.145812] [ T207531] BTRFS info (device loop0p2): found 77 extents, stage: move data extents [334357.223337] [ T207531] BTRFS info (device loop0p2): balance: ended with status: 0 [334402.346978] [ T207580] BTRFS info (device loop0p2): balance: start -mlimit=6 -slimit=6 [334402.347912] [ T207580] BTRFS info (device loop0p2): relocating block group 13431209984 flags metadata [334403.120645] [ T207580] BTRFS info (device loop0p2): found 841 extents, stage: move data extents [334403.372968] [ T207580] BTRFS info (device loop0p2): relocating block group 13162774528 flags metadata [334403.613848] [ T207580] BTRFS info (device loop0p2): found 94 extents, stage: move data extents [334403.743610] [ T207580] BTRFS info (device loop0p2): relocating block group 11820597248 flags metadata [334404.526435] [ T207580] BTRFS info (device loop0p2): found 1666 extents, stage: move data extents [334404.798554] [ T207580] BTRFS info (device loop0p2): relocating block group 4035969024 flags metadata [334406.059117] [ T207580] BTRFS info (device loop0p2): found 2363 extents, stage: move data extents [334406.374011] [ T207580] BTRFS info (device loop0p2): relocating block group 3767533568 flags metadata [334407.879438] [ T207580] BTRFS info (device loop0p2): found 5433 extents, stage: move data extents [334408.284506] [ T207580] BTRFS info (device loop0p2): relocating block group 2475687936 flags metadata [334413.884083] [ T207580] BTRFS info (device loop0p2): found 9463 extents, stage: move data extents [334414.690177] [ T207580] BTRFS info (device loop0p2): balance: ended with status: 0 [334530.694011] [ T207693] BTRFS info (device loop0p2): balance: start -dlimit=2 [334530.694839] [ T207693] BTRFS info (device loop0p2): relocating block group 12089032704 flags data [334534.205097] [ T207693] BTRFS info (device loop0p2): found 1897 extents, stage: move data extents [334534.491352] [ T207693] BTRFS info (device loop0p2): found 1897 extents, stage: update data pointers [334534.625126] [ T207693] BTRFS info (device loop0p2): relocating block group 10746855424 flags data [334536.605759] [ T207693] BTRFS info (device loop0p2): found 16316 extents, stage: move data extents [334537.056028] [ T207693] BTRFS info (device loop0p2): found 16316 extents, stage: update data pointers [334537.361629] [ T207693] BTRFS info (device loop0p2): balance: ended with status: 0 [334614.951029] [ T207803] BTRFS info (device loop0p2): dev_replace from /dev/loop0p2 (devid 1) to /dev/loop1p2 started [334654.572435] [ T207803] BTRFS info (device loop0p2): dev_replace from /dev/loop0p2 (devid 1) to /dev/loop1p2 finished So  I would need to do the same with vendor kernel on same images, I made exact copies, so can be done, however starting with vendor kernel requires system reboot (and other bootloader), so not sure when I can do this. 

You could run:
sudo apt list | grep linux-image
Besides the vanilla Debian/Ubuntu ones, there are Armbian ones: vendor, current, edge
 
In your case your installed U-Boot might be incompatible with kernel 6.1.84, I had that for my Rock3A, I installed mainline U-Boot.
 
If you want all kernels, use http://beta.armbian.com in /etc/apt/sources.list.d/armbian.list

Or build yourself from source. The Armbian build runs fine on my NanoPi-R6C Armbian Bookworm

I found the reason for the crash:  the 6.1.84-vendor-rk35xx doesn't work together with the 2024.10 mainline U-boot.
 
Earlier the SPI-flash was empty and the Rock3a booted from SD-card, a U-boot version from 2017 (Armbian_24.11.1_Rock-3a_noble_current_6.6.62-kisak.img.xz). I put that image in 'beta' mode so I got the 6.1.84-vendor-rk35xx (+ rock-3a-sata.dtbo). That all still worked.
I then put the 2024.10 mainline U-boot in SPI and wiped the sector range 34-32767 from the SD-card. Then I discovered that the 6.1.84-vendor-rk35xx always crashed, independent of SATA modules etc.
 
I now disabled the SPI and took sector range 34-32767 from the official Radxa image (rock-3a_debian_bullseye_cli_b25.img.xz) and put that on the SD-card with the Armbian Noble (latest beta channel trunk.201) and rebooted. That does not crash and works same as with 6.12.6-edge-rockchip64 that I used before the reboot to write the sector range 34-32767.
Version is:  latest-2023.07.02-3-b1eb2bde-gb1eb2bde (Aug 29 2023 - 10:43:04 +0000) 
 
So I guess I need to look at differences in uboot configs and likely also uboot sources.
 
The other thing is that If I want to be able to boot from a single SATA device with the Rockchip on-chip SATA, the uboot In the SPI-needs to default to SATA for M.2 E-key connector and not the default PCIe-2x1.
Or wait till I got an extra NVME to put in the M.2 M-key  connector and load rock-3a-sata.dtbo after uboot together with kernel. That is preferred I think looking at possible future use-cases.
 

I do not use quotas, so the fix for this issue is: https://github.com/openSUSE/snapper/issues/894#issuecomment-2054220427