20180927 LVM 邏輯卷管理

LVM, 邏輯卷管理(Logical Volume Manager)，是Linux下系統對磁盤分區進行管理的一種機制。

邏輯卷建立總體步驟：

1. 建立物理分區, 在物理分區弄好物理卷
2. 物理卷造成一個卷組
3. 在卷組的基礎上劃分邏輯卷
4. 格式化
5. 掛載

準備磁盤分區
fdisk /dev/sdb
n建立3個分區，分別爲1G
t改變分區類型爲8e

[root@centos01 ~]# fdisk /dev/sdb # 分區
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x8720953d.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-10485759, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-10485759, default 10485759): +1G
Partition 1 of type Linux and of size 1 GiB is set

Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
...

# 建立三個後輸入w保存分區退出，結果以下
[root@centos01 ~]# fdisk -l

Disk /dev/sdb: 5368 MB, 5368709120 bytes, 10485760 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x8720953d

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048     2099199     1048576   8e  Linux LVM
/dev/sdb2         2099200     4196351     1048576   8e  Linux LVM
/dev/sdb3         4196352     6293503     1048576   8e  Linux LVM

Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000b933a

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      411647      204800   83  Linux
/dev/sda2          411648     8800255     4194304   82  Linux swap / Solaris
/dev/sda3         8800256    62914559    27057152   83  Linux

準備物理卷

須要安裝物理卷工具 yum install -y lvm2
知道命令，不知道工具叫什麼時搜索對應的工具方式 yum provides "/*/pvcreate"
pvcreate /dev/sdb1 # 若是出現Device /dev/sdb1 not found (or ignored by filtering).提示，說明沒建立/dev/sdb1文件，使用partprobe命令便可生成

[root@centos01 ~]# pvcreate /dev/sdb1
WARNING: ext4 signature detected on /dev/sdb1 at offset 1080. Wipe it? [y/n]: y
  Wiping ext4 signature on /dev/sdb1.
  Physical volume "/dev/sdb1" successfully created.
[root@centos01 ~]# pvcreate /dev/sdb2
  Physical volume "/dev/sdb2" successfully created.
[root@centos01 ~]# pvcreate /dev/sdb3
  Physical volume "/dev/sdb3" successfully created.
  
[root@centos01 ~]# pvdisplay  #查看當前的物理卷，pvs命令能夠查看簡單物理卷信息
  "/dev/sdb3" is a new physical volume of "1.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb3
  VG Name
  PV Size               1.00 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               C5ebe2-eTk6-S6o2-1EC4-ZfnN-OCaq-nMinQ0

  "/dev/sdb1" is a new physical volume of "1.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb1
  VG Name
  PV Size               1.00 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               xgf99Z-OJK6-wumF-sUNu-MbTu-8fqj-qViNxN

  "/dev/sdb2" is a new physical volume of "1.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb2
  VG Name
  PV Size               1.00 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               vxsNFj-DpeA-Mhot-sp6z-QAAY-EOCx-jlo4UL


[root@centos01 ~]# pvs
  PV         VG Fmt  Attr PSize PFree
  /dev/sdb1     lvm2 ---  1.00g 1.00g
  /dev/sdb2     lvm2 ---  1.00g 1.00g
  /dev/sdb3     lvm2 ---  1.00g 1.00g

建立卷組

[root@centos01 ~]# vgcreate vg1 /dev/sdb1 /dev/sdb2
  Volume group "vg1" successfully created

建立邏輯卷

[root@centos01 ~]# lvcreate -L 100M -n lv1 vg1
  Logical volume "lv1" created.

格式化

[root@centos01 ~]# mkfs.ext4 /dev/vg1/lv1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
25688 inodes, 102400 blocks
5120 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=33685504
13 block groups
8192 blocks per group, 8192 fragments per group
1976 inodes per group
Superblock backups stored on blocks:
        8193, 24577, 40961, 57345, 73729

Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

掛載

[root@centos01 ~]# mount /dev/vg1/lv1 /mnt/
[root@centos01 ~]# df -h
Filesystem           Size  Used Avail Use% Mounted on
/dev/sda3             26G 1002M   25G   4% /
devtmpfs             489M     0  489M   0% /dev
tmpfs                494M     0  494M   0% /dev/shm
tmpfs                494M  6.7M  487M   2% /run
tmpfs                494M     0  494M   0% /sys/fs/cgroup
/dev/sda1            197M   75M  123M  38% /boot
/dev/mapper/vg1-lv1   93M  1.6M   85M   2% /mnt

# 結果中/dev/mapper/vg1-lv1與/dev/vg1/lv1指向同一個文件
[root@centos01 ~]# ls -l /dev/vg1/lv1
lrwxrwxrwx. 1 root root 7 Sep 28 10:07 /dev/vg1/lv1 -> ../dm-0
[root@centos01 ~]# ls -l /dev/mapper/vg1-lv1
lrwxrwxrwx. 1 root root 7 Sep 28 10:07 /dev/mapper/vg1-lv1 -> ../dm-0

擴容邏輯卷

lvresize -L 200M /dev/vg1/lv1 # 從新設置卷大小

[root@centos01 ~]# umount /mnt
[root@centos01 ~]# lvresize -L 200M /dev/vg1/lv1
  New size (50 extents) matches existing size (50 extents).

e2fsck -f /dev/vg1/lv1 # 檢查磁盤錯誤(ext4執行)

[root@centos01 ~]# e2fsck -f /dev/vg1/lv1
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vg1/lv1: 13/25688 files (7.7% non-contiguous), 8899/102400 blocks

resize2fs /dev/vg1/lv1 更新邏輯卷信息(ext4執行)

[root@centos01 ~]# resize2fs /dev/vg1/lv1
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vg1/lv1 to 204800 (1k) blocks.
The filesystem on /dev/vg1/lv1 is now 204800 blocks long.

縮減邏輯卷(xfs不支持)

要先umount

e2fsck -f /dev/vg1/lv1 檢查磁盤錯誤(ext)

[root@centos01 ~]# e2fsck -f /dev/vg1/lv1
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vg1/lv1: 13/49400 files (7.7% non-contiguous), 11887/204800 blocks

resize2fs /dev/vg1/lv1 更新邏輯卷信息(ext)

[root@centos01 ~]# resize2fs /dev/vg1/lv1 100M
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vg1/lv1 to 102400 (1k) blocks.
The filesystem on /dev/vg1/lv1 is now 102400 blocks long.

lvresize -L 100M /dev/vg1/lv1 從新設置卷大小

[root@centos01 ~]# lvresize -L 100M /dev/vg1/lv1
  WARNING: Reducing active logical volume to 100.00 MiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg1/lv1? [y/n]: y
  Size of logical volume vg1/lv1 changed from 200.00 MiB (50 extents) to 100.00 MiB (25 extents).
  Logical volume vg1/lv1 successfully resized.

xfs擴容邏輯卷

[root@centos01 ~]# mkfs.xfs -f /dev/vg1/lv1  # 從新格式化爲xfs
meta-data=/dev/vg1/lv1           isize=256    agcount=4, agsize=6400 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0
data     =                       bsize=4096   blocks=25600, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal log           bsize=4096   blocks=853, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

mount /dev/vg1/lv1 /mnt/


[root@centos01 ~]# xfs_growfs /dev/vg1/lv1
meta-data=/dev/mapper/vg1-lv1    isize=256    agcount=4, agsize=6400 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0
data     =                       bsize=4096   blocks=25600, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal               bsize=4096   blocks=853, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

擴展卷組

[root@centos01 ~]# vgdisplay
  --- Volume group ---
  VG Name               vg1
  System ID
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  5
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               1.99 GiB
  PE Size               4.00 MiB
  Total PE              510
  Alloc PE / Size       75 / 300.00 MiB
  Free  PE / Size       435 / <1.70 GiB
  VG UUID               wVCjMR-btBV-3oHG-zT8T-9tZF-6tRv-rSHilv

[root@centos01 ~]# vgextend vg1 /dev/sdb3
  Volume group "vg1" successfully extended
[root@centos01 ~]# vgdisplay
  --- Volume group ---
  VG Name               vg1
  System ID
  Format                lvm2
  Metadata Areas        3
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                3
  Act PV                3
  VG Size               <2.99 GiB
  PE Size               4.00 MiB
  Total PE              765
  Alloc PE / Size       75 / 300.00 MiB
  Free  PE / Size       690 / <2.70 GiB
  VG UUID               wVCjMR-btBV-3oHG-zT8T-9tZF-6tRv-rSHilv