我正在使用 Debian Jessie 构建自定义 NAS。拥有三个采用软件 RAID5 配置的 4TB 硬盘。当所有三个驱动器都存在时，工作完美。
我正在尝试测试如果驱动器坏了并且我是否可以在降级状态下启动机器时会发生什么。当我拔下任何驱动器并尝试启动计算机时，我从 grub 中看到以下内容。
Unable to find LVM volume system/root
Volume group "system" not found
Skipping volume group system
最后，grub 放弃并将我放入 initramfs shell 中。
所有三个驱动器的分区如下：
$ sudo parted /dev/sda print
Model: ATA ST4000VN000-1H41 (scsi)
Disk /dev/sda: 4001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 2097kB 1049kB bios_grub
2 2097kB 4001GB 4001GB raid
这是我的 RAID 设置...
$ sudo mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Tue Jun 30 12:56:49 2015
Raid Level : raid5
Array Size : 7813769216 (7451.79 GiB 8001.30 GB)
Used Dev Size : 3906884608 (3725.90 GiB 4000.65 GB)
Raid Devices : 3
Total Devices : 3
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Wed Jul 1 14:37:11 2015
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : kai:0 (local to host kai)
UUID : 2743ad66:6b1df25a:5c41ca14:19084f56
Events : 10286
Number Major Minor RaidDevice State
0 8 2 0 active sync /dev/sda2
1 8 18 1 active sync /dev/sdb2
2 8 34 2 active sync /dev/sdc2
逻辑卷设置...
$ sudo lvdisplay
--- Logical volume ---
LV Path /dev/system/root
LV Name root
VG Name system
LV UUID 1A55Kr-IR4x-O1Z8-YXFj-BvUJ-PMcs-uRjEsv
LV Write Access read/write
LV Creation host, time kai, 2015-06-30 12:57:39 -0400
LV Status available
# open 1
LV Size 29.80 GiB
Current LE 7629
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 4096
Block device 253:0
--- Logical volume ---
LV Path /dev/system/home
LV Name home
VG Name system
LV UUID h6Piot-XXYn-TBdK-s1Ja-YN1z-Fbdn-Nv72IT
LV Write Access read/write
LV Creation host, time kai, 2015-06-30 12:57:49 -0400
LV Status available
# open 1
LV Size 14.90 GiB
Current LE 3814
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 4096
Block device 253:2
--- Logical volume ---
LV Path /dev/system/swap
LV Name swap
VG Name system
LV UUID yh7WRj-w4OW-WV4M-q0hN-NlCx-RPiL-usSz6j
LV Write Access read/write
LV Creation host, time kai, 2015-06-30 12:57:57 -0400
LV Status available
# open 2
LV Size 3.72 GiB
Current LE 953
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 4096
Block device 253:1
--- Logical volume ---
LV Path /dev/system/storage
LV Name storage
VG Name system
LV UUID U9M7g3-sL2j-Gut6-TaNJ-BNWN-P3KM-DPpa4z
LV Write Access read/write
LV Creation host, time kai, 2015-06-30 12:58:03 -0400
LV Status available
# open 1
LV Size 7.23 TiB
Current LE 1895262
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 4096
Block device 253:3
和/etc/fstab
/dev/mapper/system-root / xfs noatime 0 1
/dev/mapper/system-home /home xfs nodev 0 2
/dev/mapper/system-storage /mnt/storage xfs nodev,noexec 0 2
/dev/mapper/system-swap none swap sw 0 0
我确实在所有三个驱动器上安装了 grub，如下所示：
$ grub-install /dev/sda
$ grub-install /dev/sdb
$ grub-install /dev/sdc
有什么想法为什么我无法启动降级的阵列吗？我很感激你的时间。