RAID

RAID 0

条带卷,优点:多块硬盘同时读写数据,提高了读写的速度
	   缺点: 一块磁盘坏了,所有的都无法用了,因为数据是分散在多块磁盘里面的,出问题的概率太大,没有容错

RAID 1

镜像卷:优点:备份,每次写入数据都会备份一份,
	   缺点:磁盘的利用率只有百分之五十,写入数据要写双倍的,写的速率下降了
   

RAID 4

3块以上的硬盘,有一块盘将其中的两块盘做异或运算,得到一个校验位 ,其中一块盘坏了,通过异或可以恢复
存放校验位的那块盘是最容易坏的

RAID 5

至少3块盘,每块盘都有一个校验位和数据,避免了像RAID4那样将校验位全部写在一块磁盘上了
可用空间l利用率: (n-1)/n

RIAD 6

升级RIAD5,每块磁盘都有两个校验位和数据,最少4块才可以完成,
磁盘的利用率 n-2/n

RAID 1 0

2块做成RAID1 另外的 2块也做成RAID1  在把这两组盘做成RAID0
利用率:50%
系统失败的几率1/3

RAID 0 1

两块组合做成RAID 0  再把这个组合备份一份
磁盘的利用率:50%
系统失败的几率2/3

逻辑卷管理--LVM

实现空间的扩展,在线扩展,不影响用户的使用情况,RAID技术扩展要关机使用
缺点:逻辑上的空间,方式不透明

#PV 将磁盘标记成为PV,
将PV组合为卷组,
从卷组里面抽取一部分成为逻辑卷

逻辑卷的划分:

可以是分区,也可以是一块物理磁盘
#拿sdb1 sdb2 记为PV
[root08:21 AMcentos8 ~]#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   50G  0 part /data
├─sda4   8:4    0    1K  0 part 
└─sda5   8:5    0    4G  0 part [SWAP]
sdb      8:16   0   20G  0 disk 
├─sdb1   8:17   0    1G  0 part 
└─sdb2   8:18   0    1G  0 part 
sr0     11:0    1  7.7G  0 rom  
[root08:25 AMcentos8 ~]#yum provides pvcreate
[root08:25 AMcentos8 ~]#yum install lvm2  -y
[root08:29 AMcentos8 ~]#rpm -ql lvm2
#查看安装该包生成了哪些命令
[root08:30 AMcentos8 ~]#rpm -ql lvm2 |grep pv
/usr/lib/systemd/system/lvm2-pvscan@.service
/usr/sbin/pvchange
/usr/sbin/pvck
/usr/sbin/pvcreate
/usr/sbin/pvdisplay
/usr/sbin/pvmove
/usr/sbin/pvremove
/usr/sbin/pvresize
/usr/sbin/pvs
/usr/sbin/pvscan
/usr/share/man/man8/pvchange.8.gz
/usr/share/man/man8/pvck.8.gz
/usr/share/man/man8/pvcreate.8.gz
/usr/share/man/man8/pvdisplay.8.gz
/usr/share/man/man8/pvmove.8.gz
/usr/share/man/man8/pvremove.8.gz
/usr/share/man/man8/pvresize.8.gz
/usr/share/man/man8/pvs.8.gz
/usr/share/man/man8/pvscan.8.gz
#相关命令
[root08:30 AMcentos8 ~]#pv
pvchange   pvck       pvcreate   pvdisplay  pvmove     pvremove   pvresize   pvs        pvscan    

#标记物理卷
[root08:35 AMcentos8 /data]#pvcreate  /dev/sdb{1,2} 
  Physical volume "/dev/sdb1" successfully created.
  Physical volume "/dev/sdb2" successfully created.

#pvdisplay  pvs 查看描述

#创建卷组,组名为mysql
[root08:37 AMcentos8 /data]#vgcreate  mysql /dev/sdb1 /dev/sdb2
  Volume group "mysql" successfully created

[root08:37 AMcentos8 /data]#vgs  查看
  VG    #PV #LV #SN Attr   VSize VFree
  mysql   2   0   0 wz--n- 1.99g 1.99g
[root08:38 AMcentos8 /data]#vgdisplay 查看卷组

#创建逻辑卷
[root08:40 AMcentos8 /data]#lvcreate -n lv_data -L  600M mysql
  Logical volume "lv_data" created.
-L表示指明具体的大小 -l表示指明的PE个数 , 例如:-l  100 表示指明PE的个数为100个
[root08:45 AMcentos8 /data]#lvs
  LV      VG    Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv_data mysql -wi-a----- 600.00m   
[root08:46 AMcentos8 /data]#ll /dev/mysql/lv_data   #在dev目录下的mysql卷组下面的lv_data逻辑卷

#生成的两条软链接的名字都是逻辑卷的名字
lrwxrwxrwx 1 root root 7 May  2 08:43 /dev/mysql/lv_data -> ../dm-0   #两条软链接
[root08:47 AMcentos8 /data]#ll /dev/mapper/mysql-lv_data 
lrwxrwxrwx 1 root root 7 May  2 08:43 /dev/mapper/mysql-lv_data -> ../dm-0

 #格式化
 [root08:56 AMcentos8 /data]#mkfs.ext4 /dev/mysql/lv_data 
[root08:59 AMcentos8 /data]#blkid |grep /dev/mapper/mysql-lv_data 
/dev/mapper/mysql-lv_data: UUID="7aacb7f6-6cdf-4aa7-ad57-f8dfa1a1295e" TYPE="ext4"

#挂载使用
[root09:01 AMcentos8 /data]#vim /etc/fstab 
[root09:04 AMcentos8 /data]#mount -a

[root09:05 AMcentos8 /data]#cp /etc/fstab  /data/mysql/
[root09:06 AMcentos8 /data]#ll /data/mysql/
total 20
-rw-r--r-- 1 root root   804 May  2 09:06 fstab
drwx------ 2 root root 16384 May  2 08:57 lost+found

pvdisplay

[root08:49 AMcentos8 /data]#pvdisplay 
  --- Physical volume ---
  PV Name               /dev/sdb1
  VG Name               mysql
  PV Size               1.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              255
  Free PE               105
  Allocated PE          150  被分配了150个PE
  PV UUID               98SCfB-ZYau-hgVd-EZEi-rq1d-eXTe-YjE6Jc
   
  --- Physical volume ---
  PV Name               /dev/sdb2
  VG Name               mysql
  PV Size               1.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              255
  Free PE               255  一个PE也没有被分配
  Allocated PE          0
  PV UUID               QUO9AV-7PuR-vzw3-RfrU-t33E-AyEz-t7XadQ
   

lvdisplay

[root08:51 AMcentos8 /data]#lvdisplay 
  --- Logical volume ---
  LV Path                /dev/mysql/lv_data
  LV Name                lv_data
  VG Name                mysql
  LV UUID                qRF7Ic-Xcol-YsVs-QIXc-pH26-uzL7-BWm3UN
  LV Write Access        read/write
  LV Creation host, time centos8.magedu.com, 2021-05-02 08:43:30 +0800
  LV Status              available
  # open                 0
  LV Size                600.00 MiB
  Current LE             150   #相当于PE
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

逻辑卷的扩展

[root09:08 AMcentos8 /data]#lvextend -L +100M /dev/mysql/lv_data   此方法直接指明大小
[root09:11 AMcentos8 /data]#lvs
  LV      VG    Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv_data mysql -wi-ao---- 700.00m       #被加了100M
  或者:此方法是以PE为单位计算的
  [root09:11 AMcentos8 /data]#lvextend -l +100%free /dev/mysql/lv_data 
全部给了逻辑卷,容量变大了
***但是看到的是文件系统空间的大小,要同步
[root09:14 AMcentos8 /data]#df  -H
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   482M     0  482M   0% /dev
tmpfs                      500M     0  500M   0% /dev/shm
tmpfs                      500M   14M  486M   3% /run
tmpfs                      500M     0  500M   0% /sys/fs/cgroup
/dev/sda2                  108G   14G   94G  13% /
/dev/sda3                   54G  1.5G   53G   3% /data
/dev/sda1                  1.1G  124M  830M  13% /boot
tmpfs                      100M     0  100M   0% /run/user/0
/dev/mapper/mysql-lv_data  603M  938k  558M   1% /data/mysql

resize2fs 同步ext系列文件系统

[root09:15 AMcentos8 /data]#resize2fs /dev/mysql/lv_data 
resize2fs 1.45.6 (20-Mar-2020)
Filesystem at /dev/mysql/lv_data is mounted on /data/mysql; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mysql/lv_data is now 522240 (4k) blocks long.

[root09:18 AMcentos8 /data]#df  -H
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   482M     0  482M   0% /dev
tmpfs                      500M     0  500M   0% /dev/shm
tmpfs                      500M   14M  486M   3% /run
tmpfs                      500M     0  500M   0% /sys/fs/cgroup
/dev/sda2                  108G   14G   94G  13% /
/dev/sda3                   54G  1.5G   53G   3% /data
/dev/sda1                  1.1G  124M  830M  13% /boot
tmpfs                      100M     0  100M   0% /run/user/0
/dev/mapper/mysql-lv_data  2.1G  1.9M  2.0G   1% /data/mysql

xfs_growfs 同步xfs 系列的文件系统

xfg_growfs mountpoint  
这一点和resize2fs 不一样

扩卷组进一步扩展逻辑卷

#标记物理机
[root09:25 AMcentos8 /data]#pvcreate /dev/sdb3
  Physical volume "/dev/sdb3" successfully created.

#扩展mysql这个卷组  
  [root09:25 AMcentos8 /data]#vgextend  mysql /dev/sdb3
  Volume group "mysql" successfully extended
#查看卷组被扩大
[root09:27 AMcentos8 /data]#vgdisplay 
  --- Volume group ---
  VG Name               mysql
  System ID             
  Format                lvm2
  Metadata Areas        3
  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                3
  Act PV                3
  VG Size               <11.99 GiB
  PE Size               4.00 MiB
  Total PE              3069
  Alloc PE / Size       510 / 1.99 GiB
  Free  PE / Size       2559 / <10.00 GiB  #有空闲空间了,被扩大了
  VG UUID               Sy9Z0L-VFTG-ZghN-ngaK-0Cjl-6Pe1-geZUbD
  
  #扩展逻辑卷组
  [root09:29 AMcentos8 /data]#lvcreate -r -L +2G /dev/mysql/lv_data 
加  -r 连带文件系统一起扩展

#加 -r  以后就无需要用resize2fs 这个命令操作一次了 
[root09:34 AMcentos8 /data]#df -h
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   460M     0  460M   0% /dev
tmpfs                      477M     0  477M   0% /dev/shm
tmpfs                      477M   13M  464M   3% /run
tmpfs                      477M     0  477M   0% /sys/fs/cgroup
/dev/sda2                  100G   13G   87G  13% /
/dev/sda3                   50G  1.4G   49G   3% /data
/dev/sda1                  976M  118M  792M  13% /boot
tmpfs                       96M     0   96M   0% /run/user/0
/dev/mapper/mysql-lv_data  4.0G  2.4M  3.8G   1% /data/mysql

逻辑卷的缩容

[root10:57 AMcentos8 ~]#pvcreate /dev/sdb{1,2}
  Physical volume "/dev/sdb1" successfully created.
  Physical volume "/dev/sdb2" successfully created.
[root10:58 AMcentos8 ~]#pvs
  PV         VG Fmt  Attr PSize PFree
  /dev/sdb1     lvm2 ---  5.00g 5.00g
  /dev/sdb2     lvm2 ---  5.00g 5.00g
[root10:58 AMcentos8 ~]#vgcreate vg0 /dev/sdb{1,2}
  Volume group "vg0" successfully created
  #所有的空间都做逻辑卷
[root10:58 AMcentos8 ~]#lvcreate -n mysql -l 100%vg  vg0
  Logical volume "mysql" created.
[root10:59 AMcentos8 ~]#lvs
  LV    VG  Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  mysql vg0 -wi-a----- 9.99g                                                    
[root10:59 AMcentos8 ~]#vgdisplay 
  --- Volume group ---
  VG Name               vg0
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               9.99 GiB
  PE Size               4.00 MiB
  Total PE              2558
  Alloc PE / Size       2558 / 9.99 GiB
  Free  PE / Size       0 / 0   
  VG UUID               24EUtO-waB2-hKy8-qEHW-Qs1D-PZ2b-sPkrhb

#格式化
[root11:00 AMcentos8 ~]#mkfs.ext4 /dev/vg0/mysql 

#挂载
[root11:03 AMcentos8 ~]#mount  /dev/vg0/mysql  /lv

#缩减逻辑卷有风险,建议先备份

1 先取消挂载
[root11:09 AMcentos8 ~]#umount   /lv

2.先检查文件系统的完整,不检查文件系统后面的步骤无法实现
[root11:12 AMcentos8 ~]#fsck -f  /dev/vg0/mysql 
fsck from util-linux 2.32.1
e2fsck 1.45.6 (20-Mar-2020)
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/mapper/vg0-mysql: 13/655360 files (0.0% non-contiguous), 66755/2619392 blocks

3 缩减文件系统
[root11:13 AMcentos8 ~]#resize2fs  /dev/vg0/mysql  1G
resize2fs 1.45.6 (20-Mar-2020)
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
[root11:15 AMcentos8 ~]#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 9.99 GiB (2558 extents) to 1.00 GiB (256 extents).
  Logical volume vg0/mysql successfully resized.

5 挂载查看容量变小
[root11:16 AMcentos8 ~]#mount /dev/vg0/mysql /lv
[root11:18 AMcentos8 ~]#df -h
Filesystem             Size  Used Avail Use% Mounted on
devtmpfs               460M     0  460M   0% /dev
tmpfs                  477M     0  477M   0% /dev/shm
tmpfs                  477M   13M  464M   3% /run
tmpfs                  477M     0  477M   0% /sys/fs/cgroup
/dev/sda2              100G   13G   87G  13% /
/dev/sda3               50G  1.4G   49G   3% /data
/dev/sda1              976M  118M  792M  13% /boot
tmpfs                   96M     0   96M   0% /run/user/0
/dev/mapper/vg0-mysql  944M   21M  857M   3% /lv
 
#/dev/vg0/mysql    /dev/mapper/vg0-mysql   都是dm-0的软链接
[root11:19 AMcentos8 ~]#ll /dev/vg0/mysql 
lrwxrwxrwx 1 root root 7 May  2 11:16 /dev/vg0/mysql -> ../dm-0
[root11:19 AMcentos8 ~]#ll /dev/mapper/vg0-mysql 
lrwxrwxrwx 1 root root 7 May  2 11:16 /dev/mapper/vg0-mysql -> ../dm-0


逻辑卷的快照

快照性能下降
空间限制,
测试用一下
#创建一个逻辑卷且格式化
[root11:45 AMcentos8 ~]#lvcreate -n binlog -L 500 vg0
[root11:45 AMcentos8 ~]#mkfs.xfs  /dev/vg0/binlog 
#自动挂载
[root11:49 AMcentos8 ~]#mount -a
# 拷贝数据到挂载目录
[root11:50 AMcentos8 /data/binlog]#cp /etc/fstab  /etc/issue /etc/os-release   /data/binlog/
#我现在的卷组里有两个逻辑卷
[root11:50 AMcentos8 /data/binlog]#lvs
  LV     VG  Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  binlog vg0 -wi-ao---- 500.00m                                                    
  mysql  vg0 -wi-ao----   1.00g      

[root11:51 AMcentos8 /data/binlog]#vgdisplay 
  --- Volume group ---
  VG Name               vg0
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               9.99 GiB
  PE Size               4.00 MiB
  Total PE              2558
  Alloc PE / Size       381 / <1.49 GiB  #已经使用的PE个数是381个
  Free  PE / Size       2177 / 8.50 GiB  #空闲的PE还有2177个
  VG UUID               24EUtO-waB2-hKy8-qEHW-Qs1D-PZ2b-sPkrhb
#创建快照要确保vg的空间还够

创建快照

[root11:51 AMcentos8 /data/binlog]#lvcreate -n binlog-snapshot -s -L 100M  /dev/vg0/binlog 
  Logical volume "binlog-snapshot" created.
-n binlog-snapshot  :创建一个叫 binlog-snapshot 的快照
-s 指明是快照,不加s 就误认为是逻辑卷
-L 100M 指明快照的大小
[root12:03 PMcentos8 /data/binlog]#lvdisplay 
  --- Logical volume ---
  LV Path                /dev/vg0/mysql
  LV Name                mysql
  VG Name                vg0
  LV UUID                ALzsqN-W5e1-dVx6-EI8a-VG1t-cv99-rruQpo
  LV Write Access        read/write
  LV Creation host, time centos8.magedu.com, 2021-05-02 10:59:47 +0800
  LV Status              available
  # open                 1
  LV Size                1.00 GiB
  Current LE             256
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0
   
  --- Logical volume ---
  LV Path                /dev/vg0/binlog
  LV Name                binlog
  VG Name                vg0
  LV UUID                5LwdHD-7Hq1-5Pvh-WCCj-7ET6-qQ5D-2CCSKj
  LV Write Access        read/write
  LV Creation host, time centos8.magedu.com, 2021-05-02 11:45:43 +0800
  LV snapshot status     source of
                         binlog-snapshot [active] #说明了什么是我的快照
  LV Status              available
  # open                 1
  LV Size                500.00 MiB
  Current LE             125
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/vg0/binlog-snapshot  3快照文件
  LV Name                binlog-snapshot
  VG Name                vg0
  LV UUID                uj3TxC-XQdi-KM1t-sakh-Y06j-JEmM-QfDf1X
  LV Write Access        read/write
  LV Creation host, time centos8.magedu.com, 2021-05-02 12:03:57 +0800
  LV snapshot status     active destination for binlog   #对binlog的快照
  LV Status              available
  # open                 0
  LV Size                500.00 MiB
  Current LE             125
  COW-table size         100.00 MiB
  COW-table LE           25
  Allocated to snapshot  0.02%
  Snapshot chunk size    4.00 KiB
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:4

[root12:13 PMcentos8 /data/binlog]#blkid 
/dev/mapper/vg0-mysql: UUID="17eee59c-438b-415a-8fd1-9426e95469de" TYPE="ext4"
/dev/mapper/vg0-binlog: UUID="e016cbb5-3e44-414f-b150-9e39f493f036" TYPE="xfs"
/dev/sda1: UUID="37e18d75-7231-4d84-8536-18e1b3a891f6" TYPE="ext4" PARTUUID="80c09a6f-01"
/dev/sda2: UUID="55d00b68-d8ef-4c35-aa11-b8c11b91e867" TYPE="xfs" PARTUUID="80c09a6f-02"
/dev/sda3: UUID="fdcd162f-2ea2-4088-9e86-6a911336304a" TYPE="xfs" PARTUUID="80c09a6f-03"
/dev/sda5: UUID="d81ef34a-c3dd-4483-b830-4cf516cbec7c" TYPE="swap" PARTUUID="80c09a6f-05"
/dev/sdb1: UUID="fwJ2ct-4fPI-3MyZ-BKHy-DB6k-d39v-hiGrto" TYPE="LVM2_member" PARTUUID="a3103b56-01"
/dev/sdb2: UUID="xtn9y9-si6o-yWdR-VSEg-zLWc-KPjO-gzbFtB" TYPE="LVM2_member" PARTUUID="a3103b56-02"
/dev/mapper/vg0-binlog--snapshot: UUID="e016cbb5-3e44-414f-b150-9e39f493f036" TYPE="xfs"

/dev/mapper/vg0-binlog 和 /dev/mapper/vg0-binlog--snapshot 的UUID是一样的,xfs文件系统无法通过uuid来挂载
[root12:16 PMcentos8 /data/binlog]#mount /dev/vg0/binlog-snapshot  /mnt/snap/
mount: /mnt/snap: wrong fs type, bad option, bad superblock on /dev/mapper/vg0-binlog--snapshot, missing codepage or helper program, or other error.
#正确的挂载方式:
[root12:17 PMcentos8 /data/binlog]#mount -o nouuid,ro   /dev/vg0/binlog-snapshot  /mnt/snap/

[root12:20 PMcentos8 /data/binlog]#ls /mnt/snap/  看到数据证明快照能备份
fstab  issue  os-release
现在我修改逻辑卷里面的东西,但是快照里面的是不会方式变化的

[root12:25 PMcentos8 /data/binlog]#ll /data/binlog/
total 12
-rw-r--r-- 1 root root 899 May  2 11:50 fstab
-rw-r--r-- 1 root root  23 May  2 11:50 issue
-rw-r--r-- 1 root root 420 May  2 11:50 os-release
[root12:25 PMcentos8 /data/binlog]#\rm /data/binlog/fstab 
[root12:26 PMcentos8 /data/binlog]#ll /mnt/snap/
total 12
-rw-r--r-- 1 root root 899 May  2 11:50 fstab   #快照里面的东西不会丢失
-rw-r--r-- 1 root root  23 May  2 11:50 issue
-rw-r--r-- 1 root root 420 May  2 11:50 os-release

#现在文件里面增加了,但是快照里面的文件是不会改变的
[root12:27 PMcentos8 /data/binlog]#touch f.txt 
[root12:28 PMcentos8 /data/binlog]#ll
total 8
-rw-r--r-- 1 root root   0 May  2 12:28 f.txt
-rw-r--r-- 1 root root  23 May  2 11:50 issue
-rw-r--r-- 1 root root 420 May  2 11:50 os-release
[root12:28 PMcentos8 /data/binlog]#ll /mnt/snap/  #发现快照里面永远都是最初的状态
total 12
-rw-r--r-- 1 root root 899 May  2 11:50 fstab
-rw-r--r-- 1 root root  23 May  2 11:50 issue
-rw-r--r-- 1 root root 420 May  2 11:50 os-release

恢复快照

#取消逻辑卷和快照的挂载
[root12:28 PMcentos8 /data/binlog]#umount /data/binlog/  /mnt/snap/

#恢复快照
[root12:31 PMcentos8 ~]#lvconvert --merge /dev/vg0/binlog-snapshot 
  Merging of volume vg0/binlog-snapshot started.
  vg0/binlog: Merged: 100.00%

#完成任务,快照自动被删除
[root12:34 PMcentos8 ~]#lvs
  LV     VG  Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  binlog vg0 -wi-a----- 500.00m                                                    
  mysql  vg0 -wi-ao----   1.00g    
 
 #查看文件被恢复 
root12:38 PMcentos8 ~]#mount -a
[root12:38 PMcentos8 ~]#ll /data/binlog/
total 12
-rw-r--r-- 1 root root 899 May  2 11:50 fstab
-rw-r--r-- 1 root root  23 May  2 11:50 issue
-rw-r--r-- 1 root root 420 May  2 11:50 os-release

快照的优点:
快 ,方便测试

pvmove移动PE

[root12:53 PMcentos8 ~]#pvdisplay 
  --- Physical volume ---
  PV Name               /dev/sdb1
  VG Name               vg0
  PV Size               5.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              1279
  Free PE               898
  Allocated PE          381
  PV UUID               fwJ2ct-4fPI-3MyZ-BKHy-DB6k-d39v-hiGrto
   
  --- Physical volume ---
  PV Name               /dev/sdb2
  VG Name               vg0
  PV Size               5.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              1279
  Free PE               1279
  Allocated PE          0
  PV UUID               xtn9y9-si6o-yWdR-VSEg-zLWc-KPjO-gzbFtB
   
[root12:53 PMcentos8 ~]#lvs
  LV     VG  Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  binlog vg0 -wi-ao---- 500.00m                                                    
  mysql  vg0 -wi-ao----   1.00g    
  
  #移动sdb1磁盘上的PE
  [root12:56 PMcentos8 ~]#pvmove /dev/sdb1  
  /dev/sdb1: Moved: 8.66%
  /dev/sdb1: Moved: 67.19%
  /dev/sdb1: Moved: 100.00%
[root12:59 PMcentos8 ~]#pvdisplay 
  --- Physical volume ---
  PV Name               /dev/sdb1    #该分区上的数据全部挪动到 /dev/sdb2 上了
  VG Name               vg0
  PV Size               5.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              1279
  Free PE               1279
  Allocated PE          0
  PV UUID               fwJ2ct-4fPI-3MyZ-BKHy-DB6k-d39v-hiGrto
   
  --- Physical volume ---
  PV Name               /dev/sdb2
  VG Name               vg0
  PV Size               5.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              1279
  Free PE               898
  Allocated PE          381
  PV UUID               xtn9y9-si6o-yWdR-VSEg-zLWc-KPjO-gzbFtB

#从卷组里删除sdb1这个成员
[root12:59 PMcentos8 ~]#vgreduce vg0 /dev/sdb1 
  Removed "/dev/sdb1" from volume group "vg0"

#从pv里面删除 sdb1 这个成员,让他不是物理卷
[root01:04 PMcentos8 ~]#pvremove /dev/sdb1
  Labels on physical volume "/dev/sdb1" successfully wiped.

#pvs彻底看不到他了
[root01:05 PMcentos8 ~]#pvs
  PV         VG  Fmt  Attr PSize  PFree 
  /dev/sdb2  vg0 lvm2 a--  <5.00g <3.51g

#fdisk 删除分区
[root01:17 PMcentos8 ~]#fdisk /dev/sdb  

[root01:17 PMcentos8 ~]#lsblk     # sdb2里就不会有内容了
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   50G  0 part /data
├─sda4           8:4    0    1K  0 part 
└─sda5           8:5    0    4G  0 part [SWAP]
sdb              8:16   0   20G  0 disk 
└─sdb2           8:18   0    5G  0 part 
  ├─vg0-mysql  253:0    0    1G  0 lvm  /data/mysql
  └─vg0-binlog 253:1    0  500M  0 lvm  /data/binlog
sr0             11:0    1 1024M  0 rom  

删除逻辑卷

1.取消所有逻辑卷的挂载,且删除/etc/fstab文件里面的挂载信息
2.删除所有的逻辑卷
[root01:26 PMcentos8 ~]#lvremove /dev/vg0/*
Do you really want to remove active logical volume vg0/mysql? [y/n]: y
3.删除卷组
[root01:27 PMcentos8 ~]#vgremove vg0
4.删除物理卷
[root01:28 PMcentos8 ~]#pvremove /dev/sdb2
 Labels on physical volume "/dev/sdb2" successfully wiped.