ARP

LVM管理

• 逻辑卷是可以跨越磁盘，可以打破上述分区方式的硬性规定，可以将多个硬盘逻辑上进行整合为一块硬盘。
• 物理卷：通常一个分区或者一个硬盘就可以建立一个物理卷，物理卷的最小单位是PE,一般默认是4MB。
• 卷组：将多个物理卷组合到一起，成为一个卷组。
• 虚拟卷：其实就是在卷组的基础上再次划分，最小单位是LE，与PE一样，并且一一对应。逻辑卷跟物理卷没有本质区别，只是站在不同的层次来看罢了。

基本分区(MBR|GPT) —-> Filesystem —-> mount
逻辑卷 —-> Filesystem —-> mount

1.创建LVM

1. 准备物理磁盘
   可以是： /dev/sdb /dev/sdc1 （建立在RIAD之上）
   [root@server0 ~]# ll /dev/vd{c,d,e}
   brw-rw—-. 1 root disk 253, 32 Jun 6 17:38 /dev/vdc
   brw-rw—-. 1 root disk 253, 48 Jun 6 17:38 /dev/vdd
   brw-rw—-. 1 root disk 253, 64 Jun 6 17:38 /dev/vde

2. pv
   [root@server0 ~]# pvcreate /dev/vdd
   Physical volume “/dev/vdd” successfully created

   [root@server0 ~]# pvscan
   PV /dev/vdd lvm2 [2.00 GiB]
   Total: 1 [2.00 GiB] / in use: 0 [0 ] / in no VG: 1 [2.00 GiB]

   [root@server0 ~]# pvs
   PV VG Fmt Attr PSize PFree
   /dev/vdd lvm2 a– 2.00g 2.00g

3. vg
   [root@server0 ~]# vgcreate vg1 /dev/vdd
   Volume group “vg1” successfully created
   [root@server0 ~]# vgs
   VG #PV #LV #SN Attr VSize VFree
   vg1 1 0 0 wz–n- 2.00g 2.00g
   [root@server0 ~]# vgscan
   Reading all physical volumes. This may take a while…
   Found volume group “vg1” using metadata type lvm2
   [root@server0 ~]# vgdisplay
   — Volume group —
   VG Name vg1
   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 2.00 GiB
   PE Size 4.00 MiB
   Total PE 511
   Alloc PE / Size 0 / 0
   Free PE / Size 511 / 2.00 GiB
   VG UUID 7E4tlj-l0a2-ph52-OytH-eaq7-58K6-2S4n8V

4. lv
   [root@server0 ~]# lvcreate -l 10 -n lv1 vg1
   [root@server0 ~]# lvcreate -L 200M -n lv2 vg1

   [root@server0 ~]# lvscan
   ACTIVE ‘/dev/vg1/lv1’ [640.00 MiB] inherit
   ACTIVE ‘/dev/vg1/lv2’ [256.00 MiB] inherit

5. 创建文件系统并挂载
   [root@server0 ~]# mkfs.xfs /dev/vg1/lv1
   [root@server0 ~]# mkfs.ext4 /dev/vg1/lv2

   [root@server0 ~]# mkdir /mnt/lv1 /mnt/lv2

   [root@server0 ~]# vim /etc/fstab
   /dev/vg1/lv1 /mnt/lv1 xfs defaults 0 0
   /dev/vg1/lv2 /mnt/lv2 ext4 defaults 0 0

   [root@server0 ~]# mount -a
   [root@server0 ~]# df
   Filesystem 1K-blocks Used Available Use% Mounted on
   /dev/mapper/vg1-lv1 651948 32928 619020 6% /mnt/lv1
   /dev/mapper/vg1-lv2 245671 2062 226406 1% /mnt/lv2

2. VG管理

扩大VG vgextend

1. pv
   [root@server0 ~]# pvcreate /dev/vde
2. vgextend
   [root@server0 ~]# vgextend vg1 /dev/vde
   Volume group “vg1” successfully extended
   [root@server0 ~]# vgs
   VG #PV #LV #SN Attr VSize VFree
   vg1 2 2 0 wz–n- 3.99g 3.76g

减小VG vgreduce

​ 1.查看当前的VG中PV的使用情况
​ [root@server0 ~]# pvs
​ PV VG Fmt Attr PSize PFree
/dev/vdd vg1 lvm2 a– 2.00g 1.76g
/dev/vde vg1 lvm2 a– 2.00g 2.00g

2. pvmove数据到其它PV
   [root@server0 ~]# pvmove /dev/vdd
   /dev/vdd: Moved: 16.7%
   /dev/vdd: Moved: 100.0%

   [root@server0 ~]# pvs
   PV VG Fmt Attr PSize PFree
   /dev/vdd vg1 lvm2 a– 2.00g 2.00g
   /dev/vde vg1 lvm2 a– 2.00g 1.76g

3. vgreduce VG
   [root@server0 ~]# vgreduce vg1 /dev/vdd
   Removed “/dev/vdd” from volume group “vg1”

   [root@server0 ~]# vgs
   VG #PV #LV #SN Attr VSize VFree
   vg1 1 2 0 wz–n- 2.00g 1.76g

3. LV扩容

1. lv扩容
   [root@server0 ~]# vgs
   VG #PV #LV #SN Attr VSize VFree
   vg1 2 2 0 wz–n- 1.88g 1.00g

   [root@server0 ~]# lvextend -L 800M /dev/vg1/lv1
   [root@server0 ~]# lvextend -L +800M /dev/vg1/lv1

   [root@server0 ~]# lvextend -l 15 /dev/vg1/lv1
   [root@server0 ~]# lvextend -l +15 /dev/vg1/lv1

   =======================================

   +50%FREE

   [root@server0 ~]# lvscan
   ACTIVE ‘/dev/vg1/lv1’ [768.00 MiB] inherit
   ACTIVE ‘/dev/vg1/lv2’ [512.00 MiB] inherit

2. FS扩容
   [root@server0 ~]# df -Th
   /dev/mapper/vg1-lv1 xfs 637M 67M 570M 11% /mnt/lv1
   /dev/mapper/vg1-lv2 ext4 240M 32M 192M 15% /mnt/lv2

   a. xfs
   [root@server0 ~]# xfs_growfs /dev/vg1/lv1

   b. ext2/3/4
   [root@server0 ~]# resize2fs /dev/vg1/lv2

   [root@server0 ~]# df -Th
   Filesystem Type Size Used Avail Use% Mounted on
   /dev/mapper/vg1-lv1 xfs 765M 67M 698M 9% /mnt/lv1
   /dev/mapper/vg1-lv2 ext4 488M 32M 429M 7% /mnt/lv2

4. LVM快照snapshot

1. 创建快照 (EXT4)
   [root@server0 ~]# lvcreate -L 128M -s -n lv2-snap /dev/vg1/lv2
   [root@server0 ~]# lvs
   LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
   lv1 vg1 -wi-ao—- 768.00m
   lv2 vg1 owi-aos— 512.00m
   lv2-snap vg1 swi-aos— 128.00m lv2 5.92

   [root@server0 ~]# mount -o ro /dev/vg1/lv2-snap /mnt/lv2-snap/

   [root@server0 ~]# df -Th
   Filesystem Type Size Used Avail Use% Mounted on
   /dev/mapper/vg1-lv2 ext4 488M 32M 429M 7% /mnt/lv2
   /dev/mapper/vg1-lv2–snap ext4 488M 32M 429M 7% /mnt/lv2-snap

   [root@server0 ~]# lvscan
   ACTIVE ‘/dev/vg1/lv1’ [768.00 MiB] inherit
   ACTIVE Original ‘/dev/vg1/lv2’ [512.00 MiB] inherit
   ACTIVE Snapshot ‘/dev/vg1/lv2-snap’ [128.00 MiB] inherit

   [root@server0 ~]# ls /mnt/lv2
   etc lost+found
   [root@server0 ~]# ls /mnt/lv2-snap/
   etc lost+found

2. 修改原卷的数据

3. 观察Snapshot
   [root@server0 ~]# lvs
   LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
   lv1 vg1 -wi-ao—- 768.00m
   lv2 vg1 owi-aos— 512.00m
   lv2-snap vg1 swi-aos— 128.00m lv2 30.56

   XFS：
   [root@server0 ~]# mount -o nouuid,ro /dev/vg1/lv1-snap /mnt/lv1-snap/s
   挂载快照，尽量使用ro（readonly）的方式，将不会破坏快照卷中的数据

   [root@server0 ~]# dmsetup ls –tree
   vg1-lv2–snap (252:5)
   ├─vg1-lv2–snap-cow (252:7)
   │ └─ (253:17)
   └─vg1-lv2-real (252:6)

   ├─ (253:17)
   └─ (253:18)
   

   vg1-lv2 (252:1)
   └─vg1-lv2-real (252:6)

   ├─ (253:17)
   └─ (253:18)
   

快照自动增长：
[root@server0 ~]# vim /etc/lvm/lvm.conf
snapshot_autoextend_threshold = 70
snapshot_autoextend_percent = 20
[root@server0 ~]# systemctl restart lvm2-monitor.service
[root@server0 ~]# systemctl enable lvm2-lvmetad.service
注：快照卷和原卷使用同一VG空间

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