问题

在引导期间组装 BTRFS 设备失败并报错：

BTRFS: too many missing devices, writeable mount is not allowed
BTRFS：丢失的设备太多，不允许可写挂载

磁盘已被错误删除

解决方案

RAID 数组中丢失的磁盘不允许挂载文件系统。

以下是来自 dmesg 的日志：

[ 44.706956] btrfs: disk space caching is enabled
[ 44.708006] btrfs: failed to read the system array on sdd1
[ 44.721272] btrfs: open_ctree failed
[ 45.437152] nr_pdflush_threads exported in /proc is scheduled for removal
[ 45.437280] sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case. If you have one, please send an email to linux-mm@kvack.org.
[ 109.750996] SELinux: initialized (dev tmpfs, type tmpfs), uses transition SIDs
[ 123.375147] device fsid 06182482-9e8c-4e92-a026-ee045ffa71df devid 1 transid 2351588 /dev/sdd1
[ 123.379134] btrfs: allowing degraded mounts
[ 123.379137] btrfs: enabling auto recovery
[ 123.379137] btrfs: disk space caching is enabled
[ 123.380401] warning devid 4 missing
[ 123.385362] btrfs: bdev (null) errs: wr 16, rd 0, flush 0, corrupt 0, gen 0
[ 123.385367] btrfs: bdev /dev/sde1 errs: wr 16, rd 0, flush 0, corrupt 0, gen 0
[ 123.446679] Btrfs: too many missing devices, writeable mount is not allowed
[ 123.457684] btrfs: open_ctree failed

RAID需要一定数量的设备才能成功挂载。
如果某些设备不存在/已失败/已被替换，我们可以尝试使用以下选项挂载文件系统并继续更新设备集。

按相同顺序尝试以下选项：

# mount -o degraded,ro /dev/sdd1 /u01
dmesg | tail

# mount -o degraded,recovery /dev/sdd1 /u01
dmesg | tail

# mount -o degraded,recovery,ro /dev/sdd1 /u01
dmesg | tail