使用 ZFS 时如何用新磁盘替换损坏的磁盘根？
我有使用 zroot 的 4 磁盘 RAIDZ2 池。这意味着 ZFS 运行在单独的分区而不是使用整个磁盘。我没有找到任何有关如何在这种情况下更换磁盘的文档，或者信息已被弃用。池是由安装自动生成的。
Camcontrol设备列表：
% doas camcontrol devlist -v
scbus0 on mpt0 bus 0:
<> at scbus0 target -1 lun ffffffff ()
scbus1 on ahcich0 bus 0:
<> at scbus1 target -1 lun ffffffff ()
scbus2 on ahcich1 bus 0:
<> at scbus2 target -1 lun ffffffff ()
scbus3 on ahcich2 bus 0:
<ST2000DM001-1CH164 CC43> at scbus3 target 0 lun 0 (pass0,ada0)
<> at scbus3 target -1 lun ffffffff ()
scbus4 on ahcich3 bus 0:
<ST2000DM001-1CH164 CC43> at scbus4 target 0 lun 0 (pass1,ada1)
<> at scbus4 target -1 lun ffffffff ()
scbus5 on ahcich4 bus 0:
<ST2000DM001-1CH164 CC43> at scbus5 target 0 lun 0 (pass2,ada2)
<> at scbus5 target -1 lun ffffffff ()
scbus6 on ahcich5 bus 0:
<SAMSUNG HD204UI 1AQ10001> at scbus6 target 0 lun 0 (pass3,ada3)
<> at scbus6 target -1 lun ffffffff ()
scbus7 on ahciem0 bus 0:
<AHCI SGPIO Enclosure 1.00 0001> at scbus7 target 0 lun 0 (pass4,ses0)
<> at scbus7 target -1 lun ffffffff ()
scbus-1 on xpt0 bus 0:
<> at scbus-1 target -1 lun ffffffff (xpt0)
现有磁盘的 gpart：
% gpart show ada0
=> 40 3907029088 ada0 GPT (1.8T)
40 1024 1 freebsd-boot (512K)
1064 984 - free - (492K)
2048 4194304 2 freebsd-swap (2.0G)
4196352 3902832640 3 freebsd-zfs (1.8T)
3907028992 136 - free - (68K)
z池状态：
% zpool status zroot
pool: zroot
state: DEGRADED
status: One or more devices has been removed by the administrator.
Sufficient replicas exist for the pool to continue functioning in a
degraded state.
action: Online the device using 'zpool online' or replace the device with
'zpool replace'.
scan: scrub repaired 28K in 0h41m with 0 errors on Thu Sep 27 17:58:02 2018
config:
NAME STATE READ WRITE CKSUM
zroot DEGRADED 0 0 0
raidz2-0 DEGRADED 0 0 0
ada0p3 ONLINE 0 0 0
ada1p3 ONLINE 0 0 0
ada2p3 ONLINE 0 0 0
15120424524672854601 REMOVED 0 0 0 was /dev/ada3p3
errors: No known data errors
离线：
% doas zpool offline zroot 15120424524672854601
我尝试将前几个 GiB 从 ada0 复制到 ada3，dd但两者都zpool attach给出zpool replace错误：/dev/ada3p3 is part of active pool 'zroot'甚至强制标志也无济于事。我猜测磁盘 UUID 发生冲突。
ada0-2p1-3如何将分区复制/复制到新磁盘 (ada3) 并更换故障驱动器的步骤是什么？自动安装程序首先运行哪些命令来创建这些分区？
答案1
第一：记住将新驱动器脱机，并确保它没有以任何方式安装或使用。
将分区表从旧磁盘复制ada0到新磁盘ada3：
% doas gpart backup ada0 | doas gpart restore -F ada3
现在ada3具有与以下相同的三个分区ada0：
% doas gpart show ada3
=> 40 3907029088 ada3 GPT (1.8T)
40 1024 1 freebsd-boot (512K)
1064 984 - free - (492K)
2048 4194304 2 freebsd-swap (2.0G)
4196352 3902832640 3 freebsd-zfs (1.8T)
3907028992 136 - free - (68K)
删除旧的 ZFS 元数据（注意分区p3）：
% doas dd if=/dev/zero of=/dev/ada3p3
更换驱动器（注意分区p3）：
% doas zpool replace -f zroot 15120424524672854601 /dev/ada3p3
Make sure to wait until resilver is done before rebooting.
If you boot from pool 'zroot', you may need to update
boot code on newly attached disk '/dev/ada3p3'.
Assuming you use GPT partitioning and 'da0' is your new boot disk
you may use the following command:
gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 da0
运行上述命令以更新新磁盘上的启动信息：
% doas gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada3
partcode written to ada3p1
bootcode written to ada3
UUID 现在不同了：
% gpart list ada0 | grep uuid | sort
rawuuid: 7f842536-bcd0-11e8-b271-00259014958c
rawuuid: 7fbe27a9-bcd0-11e8-b271-00259014958c
rawuuid: 7fe24f3e-bcd0-11e8-b271-00259014958c
% gpart list ada3 | grep uuid | sort
rawuuid: 9c629875-c369-11e8-a2b0-00259014958c
rawuuid: 9c63d063-c369-11e8-a2b0-00259014958c
rawuuid: 9c66f76e-c369-11e8-a2b0-00259014958c
% gpart list ada0 | grep efimedia | sort
efimedia: HD(1,GPT,7f842536-bcd0-11e8-b271-00259014958c,0x28,0x400)
efimedia: HD(2,GPT,7fbe27a9-bcd0-11e8-b271-00259014958c,0x800,0x400000)
efimedia: HD(3,GPT,7fe24f3e-bcd0-11e8-b271-00259014958c,0x400800,0xe8a08000)
% gpart list ada3 | grep efimedia | sort
efimedia: HD(1,GPT,9c629875-c369-11e8-a2b0-00259014958c,0x28,0x400)
efimedia: HD(2,GPT,9c63d063-c369-11e8-a2b0-00259014958c,0x800,0x400000)
efimedia: HD(3,GPT,9c66f76e-c369-11e8-a2b0-00259014958c,0x400800,0xe8a08000)
驱动器现在正在重新同步：
% zpool status zroot
pool: zroot
state: DEGRADED
status: One or more devices is currently being resilvered. The pool will
continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
scan: resilver in progress since Sat Sep 29 01:01:24 2018
64.7G scanned out of 76.8G at 162M/s, 0h1m to go
15.7G resilvered, 84.22% done
config:
NAME STATE READ WRITE CKSUM
zroot DEGRADED 0 0 0
raidz2-0 DEGRADED 0 0 0
ada0p3 ONLINE 0 0 0
ada1p3 ONLINE 0 0 0
ada2p3 ONLINE 0 0 0
replacing-3 OFFLINE 0 0 0
15120424524672854601 OFFLINE 0 0 0 was /dev/ada3p3/old
ada3p3 ONLINE 0 0 0
重新镀银后：
% zpool status zroot
pool: zroot
state: ONLINE
scan: resilvered 18.6G in 0h7m with 0 errors on Sat Sep 29 01:09:22 2018
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
ada0p3 ONLINE 0 0 0
ada1p3 ONLINE 0 0 0
ada2p3 ONLINE 0 0 0
ada3p3 ONLINE 0 0 0
errors: No known data errors