Después de probar de todo, (replace, detach, export e import ) y no poder quitar un dipositivo de log con 16.0E de espacio ALLOC :

Zpool iostat -v

                            capacity     operations    bandwidth
pool                       alloc   free   read  write   read  write
-------------------------  -----  -----  -----  -----  -----  -----

logs                           -      -      -      -      -      -
  c2t5E83A972B7F39C50d0    16.0E   238G      0      0      0      8

La solución pasa por forzar a que el espacio alloc del dispositivo sea cero : ​https://zpool.org/how-to-fix-a-stuck-zfs-log-device/

root@seal:/export/home/admin# echo ::spa -v | mdb -k
ADDR                 STATE NAME
ffffff06f8103a80    ACTIVE depot

    ADDR             STATE     AUX          DESCRIPTION
    ffffff0702cd4800 HEALTHY   -            root
    ffffff071a616800 HEALTHY   -              raidz
    ffffff071a60e800 HEALTHY   -                /dev/dsk/c2t5000CCA37DC56E8Dd0s0
    ffffff071a60f000 HEALTHY   -                /dev/dsk/c2t5000CCA37DC5E343d0s0
    ffffff071a60f800 HEALTHY   -                /dev/dsk/c2t5000CCA37DC58926d0s0
    ffffff071a611000 HEALTHY   -                /dev/dsk/c2t5000CCA37DC58956d0s0
    ffffff071a611800 HEALTHY   -                /dev/dsk/c2t5000CCA37DC3519Ad0s0
    ffffff071a612000 HEALTHY   -                /dev/dsk/c2t5000039FF3D0DF5Ed0s0
    ffffff071a612800 HEALTHY   -                /dev/dsk/c2t5000CCA37DC55170d0s0
    ffffff071a614000 HEALTHY   -                /dev/dsk/c2t5000CCA37DC4B7BDd0s0
    ffffff071a614800 HEALTHY   -                /dev/dsk/c2t5000CCA37DC53395d0s0
    ffffff071a615000 HEALTHY   -                /dev/dsk/c2t5000CCA37DC52AC1d0s0
    ffffff071a615800 HEALTHY   -                /dev/dsk/c2t5000CCA37DC5FDB8d0s0
    ffffff071a616000 HEALTHY   -                /dev/dsk/c2t5000CCA37DC56FEFd0s0

ffffff0702c7d800 HEALTHY   -              /dev/dsk/c2t5E83A972B7F39C50d0s0




root@seal:/export/home/admin# echo 'ffffff0702c7d800::print -a vdev_t vdev_stat' | mdb -k
ffffff0702c7da38 vdev_stat = {
    ffffff0702c7da38 vdev_stat.vs_timestamp = 0x385c6c823b
    ffffff0702c7da40 vdev_stat.vs_state = 0
    ffffff0702c7da48 vdev_stat.vs_aux = 0
    ffffff0702c7da50 vdev_stat.vs_alloc = 0xfffffffffffe0000
    ffffff0702c7da58 vdev_stat.vs_space = 0x3b80000000
    ffffff0702c7da60 vdev_stat.vs_dspace = 0x3b80000000
    ffffff0702c7da68 vdev_stat.vs_rsize = 0
    ffffff0702c7da70 vdev_stat.vs_esize = 0
    ffffff0702c7da78 vdev_stat.vs_ops = [ 0x2, 0x3e, 0x6, 0, 0, 0 ]
    ffffff0702c7daa8 vdev_stat.vs_bytes = [ 0, 0xf8000, 0xc000, 0, 0, 0 ]
    ffffff0702c7dad8 vdev_stat.vs_read_errors = 0
    ffffff0702c7dae0 vdev_stat.vs_write_errors = 0
    ffffff0702c7dae8 vdev_stat.vs_checksum_errors = 0
    ffffff0702c7daf0 vdev_stat.vs_self_healed = 0
    ffffff0702c7daf8 vdev_stat.vs_scan_removing = 0x1
    ffffff0702c7db00 vdev_stat.vs_scan_processed = 0
}

 echo ' ffffff0702c7da50/Z0' | mdb -kw



root@seal:/export/home/admin# echo 'ffffff0702c7da50/Z0' | mdb -kw
0xffffff0702c7da50:             0xfffffffffffe0000      =       0x0


zpool remove depot c2t5E83A972B7F39C50d0