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逻辑卷管理器总结

时间:2020-04-19 14:59:49      阅读:73      评论:0      收藏:0      [点我收藏+]

标签:directory   merge   检查   逻辑卷管理   esc   总结   rom   bytes   records   

逻辑卷管理器总结

内容概述:

  • 创建逻辑卷
  • 逻辑卷的扩展
  • 逻辑卷的缩减
  • 逻辑卷管理
  • 逻辑卷快照
  • 拆卸更换硬盘
  • 删除逻辑卷

 LVM: Logical Volume Manager 可以允许对卷进行方便操作的抽象层,包括重新设定文件系统的大小
 允许在多个物理设备间重新组织文件系统
 LVM可以弹性的更改LVM的容量

通过交换PE来进行资料的转换,将原来LV内的PE转移到其他的设备中以降低LV的容量,或将其他设备
中的PE加到LV中以加大容量

实现过程:
 将设备指定为物理卷
 用一个或者多个物理卷来创建一个卷组,物理卷是用固定大小的物理区域(Physical Extent, PE)来定义的
 在物理卷上创建的逻辑卷, 是由物理区域(PE)组成
 可以在逻辑卷上创建文件系统并挂载

范例:创建逻辑卷及逻辑卷的扩展

创建逻辑卷的相关工具(来自于lvm2包)

 [root@centos8 ~]#yum -y install lvm

 

[16:16:03 root@centos8 ~]#lsblk

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT

sda      8:0    0  200G  0 disk

├─sda1   8:1    0    1G  0 part /boot

├─sda2   8:2    0  100G  0 part /

├─sda3   8:3    0    2G  0 part [SWAP]

├─sda4   8:4    0    1K  0 part

└─sda5   8:5    0   50G  0 part /data

sdb      8:16   0    2G  0 disk

sdc      8:32   0   10G  0 disk

└─sdc1   8:33   0  500M  0 part

sr0     11:0    1    7G  0 rom  

 

1.把/dev/sdb /dev/sdc1创建为物理卷

[16:16:09 root@centos8 ~]#pvcreate /dev/sdb /dev/sdc1

 Physical volume "/dev/sdb" successfully created.

Physical volume "/dev/sdc1" successfully created.

 

 [16:16:37 root@centos8 ~]#pvs

PV         VG Fmt  Attr PSize   PFree  

 /dev/sdb      lvm2 ---    2.00g   2.00g

/dev/sdc1     lvm2 ---  500.00m 500.00m

 

2.创建卷组

 [16:17:09 root@centos8 ~]#vgcreate vg_mysql /dev/sdb /dev/sdc1

 Volume group "vg_mysql" successfully created

 

3.在物理卷上创建的逻辑卷

 [16:22:32 root@centos8 ~]#lvcreate -n lv_data -L 1.2G vg_mysql

  Rounding up size to full physical extent 1.20 GiB

 Logical volume "lv_data" created.

 

 4.指定文件系统

 [16:26:29 root@centos8 ~]#mkfs.ext4 /dev/vg_mysql/lv_data

 

 5.创建文件夹进行挂载

[16:29:14 root@centos8 ~]#mkdir /mysql/data -pv

 mkdir: created directory ‘/mysql‘

 mkdir: created directory ‘/mysql/data‘

 

6.查看逻辑卷UUID并写到/etc/fstab配置文件中使其持久挂载

 [21:17:56 root@centos8 ~]#blkid /dev/mapper/vg_mysql-lv_data

/dev/mapper/vg_mysql-lv_data: UUID="60a87f5a-d686-4003-a06b-ecf353be6b63" TYPE="ext4"

 

 [21:17:56 root@centos8 ~] vim /etc/fstab

 UUID=60a87f5a-d686-4003-a06b-ecf353be6b63 /mysql/data             ext4    defaults   0 0

 

 7.使新挂载的逻辑卷生效

 [16:31:57 root@centos8 ~]#mount -a

 

 8.逻辑卷创建完成

 [16:32:00 root@centos8 ~]#df -h

 Filesystem                    Size  Used Avail Use% Mounted on

 devtmpfs                      463M     0  463M   0% /dev

 tmpfs                         479M     0  479M   0% /dev/shm

 tmpfs                         479M  6.7M  472M   2% /run

 tmpfs                         479M     0  479M   0% /sys/fs/cgroup

 /dev/sda2                     100G  3.3G   97G   4% /

 /dev/sda5                      50G  390M   50G   1% /data

 /dev/sda1                     976M  112M  798M  13% /boot

 tmpfs                          96M     0   96M   0% /run/user/0

 /dev/mapper/vg_mysql-lv_data  1.2G  3.7M  1.1G   1% /mysql/data

 

 9.逻辑卷扩展 执行下面命令使其容量不足

[16:32:03 root@centos8 ~]#dd if=/dev/zero of=/mysql/data/big.img bs=1M count=900

900+0 records in

900+0 records out

943718400 bytes (944 MB, 900 MiB) copied, 2.85807 s, 330 MB/s

 

[16:34:40 root@centos8 ~]#df -h

Filesystem                    Size  Used Avail Use% Mounted on

devtmpfs                      463M     0  463M   0% /dev

tmpfs                         479M     0  479M   0% /dev/shm

tmpfs                         479M  6.7M  472M   2% /run

tmpfs                         479M     0  479M   0% /sys/fs/cgroup

/dev/sda2                     100G  3.3G   97G   4% /

/dev/sda5                      50G  390M   50G   1% /data

/dev/sda1                     976M  112M  798M  13% /boot

tmpfs                          96M     0   96M   0% /run/user/0

/dev/mapper/vg_mysql-lv_data  1.2G  904M  200M  82% /mysql/data

 

10.把卷组剩余的容量全部扩展给逻辑卷

[16:36:19 root@centos8 ~]#lvextend -l +100%free /dev/mapper/vg_mysql-lv_data

  Size of logical volume vg_mysql/lv_data changed from 1.20 GiB (308 extents) to 2.48 GiB (635 extents).

  Logical volume vg_mysql/lv_data successfully resized.

 

11.同步文件系统 resize2fs命令只同步extx系列 如果是xfs文件系统用xfs_growfs /mountpoint 命令扩展

[16:37:27 root@centos8 ~]#resize2fs /dev/vg_mysql/lv_data

resize2fs 1.44.6 (5-Mar-2019)

Filesystem at /dev/vg_mysql/lv_data is mounted on /mysql/data; on-line resizing required

old_desc_blocks = 1, new_desc_blocks = 1

The filesystem on /dev/vg_mysql/lv_data is now 650240 (4k) blocks long.

 

12.容量扩展成功

[16:39:14 root@centos8 ~]#df -Th

Filesystem                   Type      Size  Used Avail Use% Mounted on

devtmpfs                     devtmpfs  463M     0  463M   0% /dev

tmpfs                        tmpfs     479M     0  479M   0% /dev/shm

tmpfs                        tmpfs     479M  6.7M  472M   2% /run

tmpfs                        tmpfs     479M     0  479M   0% /sys/fs/cgroup

/dev/sda2                    xfs       100G  3.3G   97G   4% /

/dev/sda5                    xfs        50G  390M   50G   1% /data

/dev/sda1                    ext4      976M  112M  798M  13% /boot

tmpfs                        tmpfs      96M     0   96M   0% /run/user/0

/dev/mapper/vg_mysql-lv_data ext4      2.5G  904M  1.5G  39% /mysql/data

 

13.卷组没容量时把sdc剩余的空间再次扩展

[16:44:06 root@centos8 ~]#lsblk

NAME                 MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT

sda                        8:0    0  200G  0 disk

├─sda1                 8:1    0    1G  0 part /boot

├─sda2                 8:2    0  100G  0 part /

├─sda3                 8:3    0    2G  0 part [SWAP]

├─sda4                 8:4    0    1K  0 part

└─sda5                 8:5    0   50G  0 part /data

sdb                        8:16   0    2G  0 disk

└─vg_mysql-lv_data   253:0    0  2.5G  0 lvm  /mysql/data

sdc                        8:32   0   10G  0 disk

├─sdc1                 8:33   0  500M  0 part

│ └─vg_mysql-lv_data 253:0    0  2.5G  0 lvm  /mysql/data

└─sdc2                 8:34   0  9.5G  0 part

sr0                        11:0    1    7G  0 rom  

 

14.把sdc2加进vg_mgssql也就是扩展卷组

[16:45:04 root@centos8 ~]#vgextend vg_mysql /dev/sdc2

  Volume group "vg_mysql" successfully extended

 

15.同步文件系统  (加-r选项不仅扩展了空间也同步了文件系列 就不用再用resize2fs,xfs_growfs /mountpoint这两个命令单独同步了)

[16:46:16 root@centos8 ~]#lvextend -r -L +1G /dev/vg_mysql/lv_data

Size of logical volume vg_mysql/lv_data changed from 2.48 GiB (635 extents) to 3.48 GiB (891 extents).

Logical volume vg_mysql/lv_data successfully resized.

 resize2fs 1.44.6 (5-Mar-2019)

 Filesystem at /dev/mapper/vg_mysql-lv_data is mounted on /mysql/data; on-line resizing required

 old_desc_blocks = 1, new_desc_blocks = 1

 The filesystem on /dev/mapper/vg_mysql-lv_data is now 912384 (4k) blocks long.

 

 16.容量扩展成功,如果容量又不足了重复此操作

 [16:47:37 root@centos8 ~]#df -Th

 Filesystem                   Type      Size  Used Avail Use% Mounted on

 devtmpfs                     devtmpfs  463M     0  463M   0% /dev

 tmpfs                        tmpfs     479M     0  479M   0% /dev/shm

 tmpfs                        tmpfs     479M  6.7M  472M   2% /run

 tmpfs                        tmpfs     479M     0  479M   0% /sys/fs/cgroup

 /dev/sda2                    xfs       100G  3.3G   97G   4% /

 /dev/sda5                    xfs        50G  390M   50G   1% /data

 /dev/sda1                    ext4      976M  112M  798M  13% /boot

 tmpfs                        tmpfs      96M     0   96M   0% /run/user/0

 /dev/mapper/vg_mysql-lv_data ext4      3.4G  905M  2.4G  28% /mysql/data


范例:比较逻辑和普通分区的速度 可以看出逻辑卷速度明显较快

[16:50:21 root@centos8 ~]#dd if=/dev/zero of=/mysql/data/test.img bs=1M count=1024

1024+0 records in

1024+0 records out

1073741824 bytes (1.1 GB, 1.0 GiB) copied, 1.21475 s, 884 MB/s

 

[16:51:07 root@centos8 ~]#dd if=/dev/zero of=/data/test.img bs=1M count=1024

1024+0 records in

1024+0 records out

1073741824 bytes (1.1 GB, 1.0 GiB) copied, 1.99995 s, 537 MB/s



范例:逻辑卷的缩减(注意:缩减有数据损坏的风险,建议先备份再缩减,xfs文件系统不支持缩减

[10:08:46 root@centos8 ~]#blkid /dev/vg0/mysql

/dev/vg0/mysql: UUID="7a92ec02-a7cb-46a7-a869-357ef54d0bbc" TYPE="ext4"

 

[10:18:05 root@centos8 ~]#lvs

 LV    VG  Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert

  mysql vg0 -wi-a----- 2.99g                                                    

 

[10:11:17 root@centos8 ~]#df -h

Filesystem             Size  Used Avail Use% Mounted on

devtmpfs               463M     0  463M   0% /dev

tmpfs                  479M     0  479M   0% /dev/shm

tmpfs                  479M  6.7M  472M   2% /run

tmpfs                  479M     0  479M   0% /sys/fs/cgroup

/dev/sda2              100G  2.3G   98G   3% /

/dev/sda5               50G  390M   50G   1% /data

/dev/sda1              976M  112M  798M  13% /boot

tmpfs                   96M     0   96M   0% /run/user/0

/dev/mapper/vg0-mysql  2.9G  9.0M  2.8G   1% /data/mysql

 

1.取消挂载

[10:16:16 root@centos8 ~]#umount /data/mysql/

 

2.检查文件系统的完整性

[10:16:17 root@centos8 ~]#e2fsck -f /dev/vg0/mysql

e2fsck 1.44.6 (5-Mar-2019)

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/vg0/mysql: 14/196224 files (0.0% non-contiguous), 31009/784384 blocks

 

3.缩减文件系统

[10:17:36 root@centos8 ~]#resize2fs /dev/vg0/mysql 1G

resize2fs 1.44.6 (5-Mar-2019)

Resizing the filesystem on /dev/vg0/mysql to 262144 (4k) blocks.

The filesystem on /dev/vg0/mysql is now 262144 (4k) blocks long.

 

4.缩减逻辑卷

[10:21:10 root@centos8 ~]#lvreduce -L 1G /dev/vg0/mysql

  WARNING: Reducing active logical volume to 1.00 GiB.

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce vg0/mysql? [y/n]: y

  Size of logical volume vg0/mysql changed from 2.99 GiB (766 extents) to 1.00 GiB (256 extents).

  Logical volume vg0/mysql successfully resized.

 

5.重新恢复挂载

[10:21:52 root@centos8 ~]#mount

 

[10:24:17 root@centos8 ~]#lvs

LV    VG  Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert

 mysql vg0 -wi-ao---- 1.00g        

 

[10:24:26 root@centos8 ~]#df -h

Filesystem             Size  Used Avail Use% Mounted on

devtmpfs               463M     0  463M   0% /dev

tmpfs                  479M     0  479M   0% /dev/shm

tmpfs                  479M  6.7M  472M   2% /run

tmpfs                  479M     0  479M   0% /sys/fs/cgroup

/dev/sda2              100G  2.3G   98G   3% /

/dev/sda5               50G  390M   50G   1% /data

/dev/sda1              976M  112M  798M  13% /boot

tmpfs                   96M     0   96M   0% /run/user/0

/dev/mapper/vg0-mysql  944M  7.5M  870M   1% /data/mysql


范例:拆卸更换硬盘以及删除逻辑卷

 1.移走/dev/sdb1上面的数据

[11:35:22 root@centos8 mysql]#pvmove /dev/sdb1

  /dev/sdb1:Moved:60.00%

  /dev/sdb1:Moved:100.00%

 

2.从卷组中删除/dev/sdb1

 [11:35:22 root@centos8 mysql]#vgreduce vg0 /dev/sdb1

   Removed "/dev/sdb1" from volume group "vg0"

 

3.从物理卷中删除/dev/sdb1

[10:37:36 root@centos8 ~]#pvremove /dev/sdb1

 Labels on physical volume "/dev/sdb1" successfully wiped.

 

 [11:51:33 root@centos8 ~]#pvs

 PV         VG Fmt  Attr PSize PFree

  /dev/sdc      lvm2 ---  <2.00g 520.00g

 

4.拆除/dev/sdb硬盘 更换新的硬盘(同上)

 

5.删除逻辑卷

1)取消挂载

[11:41:33 root@centos8 ~]#umount /data/*

 

2)删除逻辑卷                                           

[11:50:27 root@centos8 ~]#lvremove /dev/vg0/*

Do you really want to remove active logical volume vg0/mysql? [y/n]: y

  Logical volume "mysql" successfully removed

Do you really want to remove active logical volume vg0/binlog? [y/n]: y

  Logical volume "binlog" successfully removed

 

3)删除卷组

[11:51:10 root@centos8 ~]#vgremove vg0

  Volume group "vg0" successfully removed

 

4)删除物理卷

[11:51:39 root@centos8 ~]#pvremove /dev/sdc

  Labels on physical volume "/dev/sdc" successfully wiped.

 

5)逻辑卷删除完成

[11:51:53 root@centos8 ~]#pvs

 

[11:51:56 root@centos8 ~]#blkid

/dev/sda1: UUID="377d3ae3-d461-4b9a-bc5d-361f0ea59252" TYPE="ext4" PARTUUID="6b9d8abc-01"

/dev/sda2: UUID="40baacb1-d7d2-4f10-9e4a-97aeb1fc149e" TYPE="xfs" PARTUUID="6b9d8abc-02"

/dev/sda3: UUID="bc09f73c-61fe-4ff0-b47e-5b177b0764bb" TYPE="swap" PARTUUID="6b9d8abc-03"

/dev/sda5: UUID="ce7a0445-cc13-4e9b-b52f-83b46bf24a4b" TYPE="xfs" PARTUUID="6b9d8abc-05"

/dev/sr0: UUID="2020-01-03-21-42-40-00" LABEL="CentOS-8-1-1911-x86_64-dvd" TYPE="iso9660" PTUUID="087a73cc" PTTYPE="dos"

/dev/sdb: PTUUID="88b1ac1c" PTTYPE="dos"

 

[12:00:43 root@centos8 ~]#lsblk

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT

sda      8:0    0  200G  0 disk

├─sda1   8:1    0    1G  0 part /boot

├─sda2   8:2    0  100G  0 part /

├─sda3   8:3    0    2G  0 part [SWAP]

├─sda4   8:4    0    1K  0 part

└─sda5   8:5    0   50G  0 part /data

sdb      8:16   0   20G  0 disk

sdc      8:32   0    2G  0 disk

sr0     11:0    1    7G  0 rom  


逻辑卷快照工作原理

  • 在生成快照时会分配给它一定的空间,但只有在原来的逻辑卷或者快照有所改变才会使用这些空间
  • 当原来的逻辑卷中有所改变时,会将旧的数据复制到快照中
  • 快照中只含有原来的逻辑卷中更改的数据或者自生成快照后的快照中更改的数据

快照特点:

  • 备份速度快,瞬间完成
  • 应用场景是测试环境,不能完成代替备份
  • 快照后,逻辑卷的修改速度会一定有影响

 

范例:为现有逻辑卷创建快照

1.逻辑卷快照

mkfs.xfs /dev/vg0/data

mount /dev/vg0/data/  /mnt/data

 

2.创建逻辑卷现有快照

lvcreate -l 64 -s -n data-snapshot -p r /dev/vg0/data

 

3.挂载快照

mkdir  -p  /mnt/snap

mount -o ro /dev/vg0/data-snapshot   /mnt/snap

 

4.恢复快照

umount /dev/vg0/data-snapshot

umount /dev/vg0/data

lvconvert --merge /dev/vg0/data-snapshot

 

5.删除快照

umount  /mnt/databackup

lvremove  /dev/vg0/databackup

 

逻辑卷管理器总结

标签:directory   merge   检查   逻辑卷管理   esc   总结   rom   bytes   records   

原文地址:https://www.cnblogs.com/chailonggang/p/12726273.html

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