预备知识
逻辑卷管理LVM是一个硬盘系统工具。无论在Linux或者其他类似的系统，都是非常的好用。传统分区使用固定大小分区，重新调整大小十分麻烦。但是，LVM可以创建和管理“逻辑”卷，而不是直接使用物理硬盘。可以让管理员弹性的管理逻辑卷的扩大缩小，操作简单，而不损坏已存储的数据。可以随意将新的硬盘添加到LVM，以直接扩展已经存在的逻辑卷。LVM并不需要重启就可以让内核知道分区的存在。
lvm
图中顶部，首先是实际的物理磁盘及其划分的分区和其上的物理卷（PV）。一个或多个物理卷可以用来创建卷组（VG）。然后基于卷组可以创建逻辑卷（LV）。只要在卷组中有可用空间，就可以随心所欲的创建逻辑卷。文件系统就是在逻辑卷上创建的，然后可以在操作系统挂载和访问。
pv/vg/lv
磁盘的扩容主要依据就是lvm
磁盘信息
-
lsblk与df -hT
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 17.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk
[root@micocube ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_micocube-lv_root
ext4 18G 1.9G 15G 12% /
tmpfs tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 ext4 477M 41M 412M 9% /boot
- 可以看到sdb的类型是disk，没有分区，也没有挂载点，就是个空白盘
将空白磁盘直接格式化，挂载到/data
- 如何将其挂上去用呢？最简单的方法，就是将整个磁盘格式化，不分区，直接使用，但是用这种方法之后磁盘不再支持扩容
[root@micocube ~]# mkfs -t ext4 /dev/sdb
mke2fs 1.41.12 (17-May-2010)
/dev/sdb is entire device, not just one partition!
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
655360 inodes, 2621440 blocks
131072 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2684354560
80 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 29 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
- 临时挂载
[root@micocube ~]# mkdir /data
[root@micocube ~]# mount /dev/sdb /data/
[root@micocube ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_micocube-lv_root
ext4 18G 1.9G 15G 12% /
tmpfs tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 ext4 477M 41M 412M 9% /boot
/dev/sdb ext4 9.8G 23M 9.2G 1% /data
- 永久挂载
[root@micocube ~]# vi /etc/fstab
#
# /etc/fstab
# Created by anaconda on Sun Apr 28 05:50:32 2019
#
# 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/vg_micocube-lv_root / ext4 defaults 1 1
UUID=57ad23fa-8c2f-42f8-91c1-01e5bcf4a058 /boot ext4 defaults 1 2
/dev/mapper/vg_micocube-lv_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
/dev/sdb /data ext4 defaults 0 0
# reboot
[root@micocube ~]# reboot
[root@micocube ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_micocube-lv_root
ext4 18G 1.9G 15G 12% /
tmpfs tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 ext4 477M 41M 412M 9% /boot
/dev/sdb ext4 9.8G 23M 9.2G 1% /data
## 可以看到sdb已经挂载上去了
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 17.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk
如果想给/(根)挂载点扩容，咋办？
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 17.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk /data
可以看到/根挂载点的类型是lvm，这说明他可以动态扩容，为了试验，我加了一块15G的硬盘:
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 17.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk /data
sdc 8:32 0 15G 0 disk
- 接下来我会把sdc扩容到dev/vg_micocube/lv_root 即/节点
- 给sdc分区，为了方便，这里只分一个区,注意代码8e，即Changed system type of partition 1 to 8e (Linux LVM)，分区的系统类型修改为lvm，
[root@micocube ~]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x66a87408.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-1958, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1958, default 1958):
Using default value 1958
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdc: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 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: 0x66a87408
Device Boot Start End Blocks Id System
/dev/sdc1 1 1958 15727603+ 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
- 接着创建pv，扩展vg，扩展lv，resize2fs
[root@micocube ~]# pvcreate /dev/sdc1
Physical volume "/dev/sdc1" successfully created
## 查看所有vg
[root@micocube ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg_micocube 1 2 0 wz--n- 19.51g 0
## 扫描vg
[root@micocube ~]# vgscan
Reading all physical volumes. This may take a while...
Found volume group "vg_micocube" using metadata type lvm2
[root@micocube ~]# vgextend vg_micocube /dev/sdc1
[root@micocube ~]# lvextend -L +15G /dev/mapper/vg_micocube-lv_root
Insufficient free space: 3840 extents needed, but only 3839 available
[root@micocube ~]# lvextend -L +14G /dev/mapper/vg_micocube-lv_root
Size of logical volume vg_micocube/lv_root changed from 17.51 GiB (4482 extents) to 31.51 GiB (8066 extents).
Logical volume lv_root successfully resized.
[root@micocube ~]# df -hlT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_micocube-lv_root
ext4 18G 1.9G 15G 12% /
tmpfs tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 ext4 477M 41M 412M 9% /boot
/dev/sdb ext4 9.8G 23M 9.2G 1% /data
[root@micocube ~]# resize2fs -f /dev/mapper/vg_micocube-lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_micocube-lv_root is mounted on /; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 2
Performing an on-line resize of /dev/mapper/vg_micocube-lv_root to 8259584 (4k) blocks.
The filesystem on /dev/mapper/vg_micocube-lv_root is now 8259584 blocks long.
[root@micocube ~]# df -hlT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_micocube-lv_root
ext4 31G 1.9G 28G 7% /
tmpfs tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 ext4 477M 41M 412M 9% /boot
/dev/sdb ext4 9.8G 23M 9.2G 1% /data
### 可以看到已经扩容成功了
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk /data
sdc 8:32 0 15G 0 disk
└─sdc1 8:33 0 15G 0 part
└─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
如果想给/data节点扩容呢？
emmm，我又重新添加了一块磁盘sdd:
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk /data
sdc 8:32 0 15G 0 disk
└─sdc1 8:33 0 15G 0 part
└─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
sdd 8:48 0 20G 0 disk
- 先卸载sdb,
umount /dev/sdb或者umount /data
## 将之前写入分区表的 /dev/sdb /data ext4 defaults 0 0 这一行删除
[root@micocube ~]# vi /etc/fstab
[root@micocube ~]# umount /dev/sdb
umount: /data: device is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))
[root@micocube ~]# fuser -m -v /dev/sdb
USER PID ACCESS COMMAND
/data/: root 1895 F.... bash
### 这一步可能连接会断，毕竟你用到了/data 重连就好了
- 因为没有分区，不是lvm类型，肯定是扩容不了的，只能给磁盘重新分区
[root@micocube ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xe7603f99.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
### 我想直接改变类型，行不通，只能重新创建分区
Command (m for help): t
No partition is defined yet!
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-1305, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1305, default 1305):
Using default value 1305
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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: 0xe7603f99
Device Boot Start End Blocks Id System
/dev/sdb1 1 1305 10482381 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
- 在进行下一步之前，我还想再强调一下pv/vg/lv的关系
一个硬盘分区组成一个pv（物理卷）
一个或者多个pv组成一个vg（卷组）
一个vg可以划分出多个lv（逻辑卷） - 创建pv
## 用分区/dev/sdb1创建一个pv
[root@micocube ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
## 这一阶段并没有什么变化
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk
└─sdb1 8:17 0 10G 0 part
sdc 8:32 0 15G 0 disk
└─sdc1 8:33 0 15G 0 part
└─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
sdd 8:48 0 20G 0 disk
- 如果sdb1找不到可以试着重读分区表
## 重读分区表
[root@micocube ~]# partprobe
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (Device or resource busy). As a result, it may not reflect all of your changes until after reboot.
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sdc (Device or resource busy). As a result, it may not reflect all of your changes until after reboot.
Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only.
- 创建vg
## 用pv(/dev/sdb1)创建一个vg
[root@micocube ~]# vgcreate vg_data /dev/sdb1
Volume group "vg_data" successfully created
- 查看所有vg
## 查看创建的vg
[root@micocube ~]# vgdisplay
--- Volume group ---
VG Name vg_data
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 9.99 GiB
PE Size 4.00 MiB
Total PE 2558
Alloc PE / Size 0 / 0
Free PE / Size 2558 / 9.99 GiB
VG UUID iyB24d-X5KM-mhKR-Lxw1-kL9i-VALO-ez4EnG
--- Volume group ---
VG Name vg_micocube
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 5
VG Access read/write
VG Status resizableF
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size 34.50 GiB
PE Size 4.00 MiB
Total PE 8833
Alloc PE / Size 8578 / 33.51 GiB
Free PE / Size 255 / 1020.00 MiB
VG UUID KBuu3K-sZ9j-NdYo-RaK3-ajJs-UAQm-3NJK53
- 创建lv
## -L 后面是分给lv的大小，-n 新建名字为vg_data的lv，所属卷组(vg)为vg_data
[root@micocube ~]# lvcreate -L 9.99G -n vg_data vg_data
Rounding up size to full physical extent 9.99 GiB
Logical volume "vg_data" created.
- 格式化lv
## dev后边第一个是vg 第二个是lv
[root@micocube ~]# mkfs.ext4 /dev/vg_data/vg_data
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
655360 inodes, 2619392 blocks
130969 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2684354560
80 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
- 永久挂载
[root@micocube ~]# vi /etc/fstab
#
# /etc/fstab
# Created by anaconda on Sun Apr 28 05:50:32 2019
#
# 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/vg_micocube-lv_root / ext4 defaults 1 1
UUID=57ad23fa-8c2f-42f8-91c1-01e5bcf4a058 /boot ext4 defaults 1 2
/dev/mapper/vg_micocube-lv_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
/dev/vg_data/vg_data /data ext4 defaults 0 0
- 重新挂载
### 重新挂载,使/etc/fstab生效
[root@micocube ~]# mount -a
- 为了测试扩容后数据是否丢失
#### 按惯例先写一些文件，看扩容后是否还存在
[root@micocube ~]# echo 111111111111 >/data/a.txt
[root@micocube ~]# echo 222222222222 >/data/b.txt
[root@micocube ~]# echo 333333333333 >/data/c.txt
[root@micocube ~]# ls /data/
a.txt b.txt c.txt lost+found
[root@micocube ~]# cat /data/*.txt
111111111111
222222222222
333333333333
- 给sdd分区
### sdd分区
[root@micocube ~]# fdisk /dev/sdd
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x7a10ae95.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610):
Using default value 2610
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdd: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x7a10ae95
Device Boot Start End Blocks Id System
/dev/sdd1 1 2610 20964793+ 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
- 创建pv
### 创建pv
[root@micocube ~]# pvcreate /dev/sdd1
Physical volume "/dev/sdd1" successfully created
[root@micocube ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg_data 1 1 0 wz--n- 9.99g 0
vg_micocube 2 2 0 wz--n- 34.50g 1020.00m
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk
└─sdb1 8:17 0 10G 0 part
└─vg_data-vg_data (dm-2) 253:2 0 10G 0 lvm /data
sdc 8:32 0 15G 0 disk
└─sdc1 8:33 0 15G 0 part
└─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
sdd 8:48 0 20G 0 disk
└─sdd1 8:49 0 20G 0 part
- 将创建的pv扩展到vg_data卷组中
## 将创建的pv扩展到vg_data卷组中
[root@micocube ~]# vgextend vg_data /dev/sdd1
Volume group "vg_data" successfully extended
- 扩展lv
## 扩展lv
[root@micocube ~]# lvextend -L +20G /dev/vg_data/vg_data
Insufficient free space: 5120 extents needed, but only 5118 available
[root@micocube ~]# lvextend -L +19.9G /dev/vg_data/vg_data
Rounding size to boundary between physical extents: 19.90 GiB.
Size of logical volume vg_data/vg_data changed from 9.99 GiB (2558 extents) to 29.89 GiB (7653 extents).
Logical volume vg_data successfully resized.
- resize2fs 使扩展生效
## 写入扩展
[root@micocube ~]# resize2fs -f /dev/vg_data/vg_data
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg_data/vg_data is mounted on /data; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 2
Performing an on-line resize of /dev/vg_data/vg_data to 7836672 (4k) blocks.
The filesystem on /dev/vg_data/vg_data is now 7836672 blocks long.
### 可以看到sdb和sdd已经合并了
[root@micocube ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 55.3M 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
└─vg_micocube-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk
└─sdb1 8:17 0 10G 0 part
└─vg_data-vg_data (dm-2) 253:2 0 29.9G 0 lvm /data
sdc 8:32 0 15G 0 disk
└─sdc1 8:33 0 15G 0 part
└─vg_micocube-lv_root (dm-0) 253:0 0 31.5G 0 lvm /
sdd 8:48 0 20G 0 disk
└─sdd1 8:49 0 20G 0 part
└─vg_data-vg_data (dm-2) 253:2 0 29.9G 0 lvm /data
- 检查文件是否丢失
### 检查文件是否丢失
[root@micocube ~]# ls /data/
a.txt b.txt c.txt lost+found
[root@micocube ~]# cat /data/*.txt
111111111111
222222222222
333333333333
### 未丢失
一次给oracle数据库盘扩容的经历
- 接手的时候，oracle数据库文件在一个磁盘(/dev/vdb)的vdb7分区里，即类型为part，挂载点为/database/db1，也就是说，没有建lvm(逻辑卷管理)，直接格式化分区,数据库文件全在里边(dbf),150G，已经用了差不多99%，另外加了一块600G的空白磁盘(/dev/vdc)很明显，是不能直接扩容的，因为是开发环境，那就有的搞了，随便停机多久都没问题啊
- 思路
- 将vdc分区(/dev/sdc1)，分区系统类型为lvm，创建pv/vg(vg_data)/lv(vg_data_lv),挂载到/db/temp(之前不存在)文件夹
- 将/database/db1/下的所有文件拷贝到/db/temp,
cp -R /database/db1/* /db/temp/ - vd7 已经是part类型了，那就直接创建pv,之后
vgextend vg_data /dev/vdb7,扩展/dev/vdb7到vg_data卷组，lvextend -L +150G /dev/vg_data/vg_data_lv，将原本的150G分配给/dev/vg_data/vg_data_lv resize2fs -f /dev/vg_data/vg_data_lv- 扩容成功之后将/dev/vg_data/vg_data_lv永久挂载到
/database/db1
- 意外：
- resize2fs 报错kernel does not support online resizing：先将
/dev/vg_data/vg_data_lv卸载(umount /dev/vg_data/vg_data_lv),再执行resize2fs -f /dev/vg_data/vg_data_lv，之后挂载(mount -a),参考连接：‘filesystem not support online resizing’ 错误 - 扩容之后数据库起不来了，报错：ORA-00205: error in identifying control file, check alert log for more info,造成这个问题的原因是oracle用户访问不了/database/db1，因为扩容的时候用的是root用户创建的，所以没权限，更改用户所属组就好了，
chown -R oracle:dba /database/db1就好了.参考连接：ORACLE11g 实例启动报错 ORA-00205: error in identifying control file, check alert log for more info
- resize2fs 报错kernel does not support online resizing：先将
总结
- 使用空白磁盘的时候不要直接格式化整个磁盘，最少给磁盘分个区，分区系统类型设置为lvm(8e),再创建pv/vg/lv，要不然以后扩容麻烦
- lvextend命令最好再加上-r 参数
lvextend -r -l +100%FREE /dev/mapper/VolGroup-lv_home
如果不加 -r 参数，需要手动使用 resize2fs /dev/mapper/VolGroup-lv_home才能生效。
lvm 的常用操作
| lv/pv/vg | 查看显示 | 创建 | 删除 | 扩容 | 激活 | 扫描查找 |
|---|---|---|---|---|---|---|
| LV | lvdisplay | lvcreate | lvremove | lvextend | lvchange | lvscan |
| PV | pvdisplay | pvcreate | pvremove | pvchange | pvscan | |
| VG | vgdisplay | vgcreate | vgremove | vgextend | vgchange | vgscan |
参考链接
RedHat/CentOS根目录扩容
linux分区满了，如何进行扩容
【linux】新添加一块硬盘制作LVM卷并进行分区挂载
故障处理：磁盘扩容出错：e2fsck: Bad magic number in super-block while trying to open /dev/vdb1