因客户检修断电，来电后发现数据库恢复正常，但备份磁盘的分区丢失，如下图
[root@db1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/LVMgroup-root
99G 9.7G 84G 11% /
tmpfs 252G 805M 252G 1% /dev/shm
/dev/sda1 477M 81M 367M 19% /boot
/dev/mapper/LVMgroup-u01 558G 15G 515G 3% /u01
[root@db1 ~]# blkid |grep asm-backupp1
[root@db1 ~]# cat /etc/fstab
#
# /etc/fstab
# Created by anaconda on Thu Sep 6 04:07:09 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/LVMgroup-root / ext4 defaults 0 0
UUID=6b99d5ae-4e0b-42a5-94af-7b29a5892f2f /boot ext4 defaults 0 0
/dev/mapper/LVMgroup-u01 /u01 ext4 defaults 1 2
/dev/mapper/LVMgroup-swap swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
asm-backupp1 /backup ext4 defaults 0 0
/dev/mapper/asm-backupp1 /backup ext4 defaults 0 0
[root@db1 ~]# mount -a
mount: special device /dev/mapper/asm-backupp1 does not exist
[root@db1 ~]# multipath -ll
asm-backup (3683df501009697e0307131667a026101) dm-11 HUAWEI,VIS6000
size=2.0T features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 6:0:0:10 sdk 8:160 active ready running
|- 8:0:0:10 sdae 65:224 active ready running
|- 6:0:1:10 sdu 65:64 active ready running
`- 8:0:1:10 sdao 66:128 active ready running
[root@db1 ~]# fdisk -l /dev/mapper/asm-backup
WARNING: GPT (GUID Partition Table) detected on '/dev/mapper/asm-backup'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/mapper/asm-backup: 2199.0 GB, 2199023255552 bytes
255 heads, 63 sectors/track, 267349 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/mapper/asm-backupp1 1 267350 2147483647+ ee GPT
[root@db1 ~]# parted /dev/mapper/asm-backup
GNU Parted 2.1
Using /dev/mapper/asm-backup
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p
Model: Linux device-mapper (multipath) (dm)
Disk /dev/mapper/asm-backup: 2199GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 17.4kB 2199GB 2199GB ext4 backup
(parted)
[root@db1 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 1.1T 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 1.1T 0 part
├─LVMgroup-swap (dm-0) 251:0 0 200G 0 lvm [SWAP]
├─LVMgroup-root (dm-1) 251:1 0 100G 0 lvm /
├─LVMgroup-tmp (dm-12) 251:12 0 50G 0 lvm /tmp
├─LVMgroup-var (dm-13) 251:13 0 100G 0 lvm /var
├─LVMgroup-u01 (dm-14) 251:14 0 566.3G 0 lvm /u01
└─LVMgroup-usr (dm-15) 251:15 0 100G 0 lvm /usr
sdk 8:160 0 2T 0 disk
└─asm-backup (dm-11) 251:11 0 2T 0 mpath
sdu 65:64 0 2T 0 disk
└─asm-backup (dm-11) 251:11 0 2T 0 mpath
sdae 65:224 0 2T 0 disk
└─asm-backup (dm-11) 251:11 0 2T 0 mpath
sdao 66:128 0 2T 0 disk
└─asm-backup (dm-11) 251:11 0 2T 0 mpath
最终办法：
[root@db1 ~]# partprobe /dev/mapper/asm-backup
You have mail in /var/spool/mail/root
[root@db1 ~]# blkid |grep asm-backupp1
/dev/mapper/asm-backupp1: UUID="ca2353fe-6e16-4c8d-bff7-8ea3032e1bbe" TYPE="ext4"
[root@db1 ~]# mount -a
[root@db1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/LVMgroup-root
99G 9.7G 84G 11% /
tmpfs 252G 805M 252G 1% /dev/shm
/dev/sda1 477M 81M 367M 19% /boot
/dev/mapper/LVMgroup-u01
558G 15G 515G 3% /u01
/dev/mapper/asm-backupp1 2.0T 333G 1.6T 18% /backup