1、故障描述（ 在線移除一塊被設置爲pv格式的硬盤，提示unknown device報道）：
/dev/sdb1 /dev/sdc1 /dev/sdd1是組成/dev/vg_test/lvm_test的PV，這裏我們模擬/dev/sdd1硬盤被直接斷電了
[root@docker mnt]# pvdisplay /dev/sdd: read failed after 0 of 4096 at 0: Input/output error /dev/sdd: read failed after 0 of 4096 at 21474770944: Input/output error /dev/sdd: read failed after 0 of 4096 at 21474828288: Input/output error /dev/sdd: read failed after 0 of 4096 at 4096: Input/output error /dev/sdd1: read failed after 0 of 512 at 21467824128: Input/output error /dev/sdd1: read failed after 0 of 512 at 21467938816: Input/output error /dev/sdd1: read failed after 0 of 512 at 0: Input/output error /dev/sdd1: read failed after 0 of 512 at 4096: Input/output error /dev/sdd1: read failed after 0 of 2048 at 0: Input/output error Couldn't find device with uuid 166hLZ-2POl-GIsv-ELGh-8YVT-Zcoa-ZcLXzp. --- Physical volume --- PV Name /dev/sdb1 VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 5118 Free PE 0 Allocated PE 5118 PV UUID fuQdIY-qkJw-fZJB-AauO-Zqpj-91RI-S1GG0X --- Physical volume --- PV Name /dev/sdc1 VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes PE Size 4.00 MiB Total PE 5118 Free PE 5116 Allocated PE 2 PV UUID TRlpMQ-snM6-u24f-cMHa-oiVt-XJ3w-6fjAbp --- Physical volume --- PV Name unknown device VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes PE Size 4.00 MiB Total PE 5118 Free PE 5118 Allocated PE 0 PV UUID 166hLZ-2POl-GIsv-ELGh-8YVT-Zcoa-ZcLXzp
[root@docker mnt]# vgreduce --removemissing vg_test
/dev/sdd: read failed after 0 of 4096 at 0: Input/output error /dev/sdd1: read failed after 0 of 2048 at 0: Input/output error /dev/sdd: read failed after 0 of 4096 at 21474770944: Input/output error /dev/sdd: read failed after 0 of 4096 at 21474828288: Input/output error /dev/sdd: read failed after 0 of 4096 at 4096: Input/output error /dev/sdd1: read failed after 0 of 512 at 21467824128: Input/output error /dev/sdd1: read failed after 0 of 512 at 21467938816: Input/output error /dev/sdd1: read failed after 0 of 512 at 0: Input/output error /dev/sdd1: read failed after 0 of 512 at 4096: Input/output error Couldn't find device with uuid 166hLZ-2POl-GIsv-ELGh-8YVT-Zcoa-ZcLXzp. Wrote out consistent volume group vg_test
[root@docker mnt]# vgchange -a y
/dev/sdd: read failed after 0 of 4096 at 0: Input/output error /dev/sdd1: read failed after 0 of 2048 at 0: Input/output error 1 logical volume(s) in volume group "vg_test" now active
[root@docker mnt]# df -h
Filesystem Size Used Avail Use% Mounted on /dev/sda3 193G 14G 170G 8% / tmpfs 1.9G 228K 1.9G 1% /dev/shm /dev/sda1 190M 80M 100M 45% /boot /dev/mapper/vg_test-lvm_test 20G 28M 19G 1% /mnt
[root@docker mnt]# pvdisplay
/dev/sdd: read failed after 0 of 4096 at 0: Input/output error /dev/sdd: read failed after 0 of 4096 at 21474770944: Input/output error /dev/sdd: read failed after 0 of 4096 at 21474828288: Input/output error /dev/sdd: read failed after 0 of 4096 at 4096: Input/output error /dev/sdd1: read failed after 0 of 512 at 21467824128: Input/output error /dev/sdd1: read failed after 0 of 512 at 21467938816: Input/output error /dev/sdd1: read failed after 0 of 512 at 0: Input/output error /dev/sdd1: read failed after 0 of 512 at 4096: Input/output error /dev/sdd1: read failed after 0 of 2048 at 0: Input/output error --- Physical volume --- PV Name /dev/sdb1 VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 5118 Free PE 0 Allocated PE 5118 PV UUID fuQdIY-qkJw-fZJB-AauO-Zqpj-91RI-S1GG0X --- Physical volume --- PV Name /dev/sdc1 VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes PE Size 4.00 MiB Total PE 5118 Free PE 5116 Allocated PE 2 PV UUID TRlpMQ-snM6-u24f-cMHa-oiVt-XJ3w-6fjAbp
發現仍舊有I/O的錯誤出現，跳過重啓系統，故障得到解決(這裏注意重啓前檢查fatab信息，看下mount -a是否有報錯）。
[root@docker ~]# pvdisplay --- Physical volume --- PV Name /dev/sdb1 VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 5118 Free PE 0 Allocated PE 5118 PV UUID fuQdIY-qkJw-fZJB-AauO-Zqpj-91RI-S1GG0X --- Physical volume --- PV Name /dev/sdc1 VG Name vg_test PV Size 19.99 GiB / not usable 1.43 MiB Allocatable yes PE Size 4.00 MiB Total PE 5118 Free PE 5116 Allocated PE 2 PV UUID TRlpMQ-snM6-u24f-cMHa-oiVt-XJ3w-6fjAbp