Linux中vgextend的含义,每天一点Linux

8种机械键盘轴体对比

本人程序员，要买一个写代码的键盘，请问红轴和茶轴怎么选？

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准备物理磁盘

可以是： /dev/sdb /dev/sdc1 (建立在RIAD之上)

[[email protected] ~]# 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

pv

[[email protected] ~]# pvcreate /dev/vdd

Physical volume “/dev/vdd” successfully created

[[email protected] ~]# pvscan

PV /dev/vdd lvm2 [2.00 GiB]

Total: 1 [2.00 GiB] / in use: 0 [0 ] / in no VG: 1 [2.00 GiB]

[[email protected] ~]# pvs

PV VG Fmt Attr PSize PFree

/dev/vdd lvm2 a– 2.00g 2.00g

vg

[[email protected] ~]# vgcreate vg1 /dev/vdd

Volume group “vg1” successfully created

[[email protected] ~]# vgs

VG #PV #LV #SN Attr VSize VFree

vg1 1 0 0 wz–n- 2.00g 2.00g

[[email protected] ~]# vgscan

Reading all physical volumes. This may take a while…

Found volume group “vg1” using metadata type lvm2

[[email protected] ~]# 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

lv

[[email protected] ~]# lvcreate -l 10 -n lv1 vg1

[[email protected] ~]# lvcreate -L 200M -n lv2 vg1

[[email protected] ~]# lvscan

ACTIVE ‘/dev/vg1/lv1’ [640.00 MiB] inherit

ACTIVE ‘/dev/vg1/lv2’ [256.00 MiB] inherit

创建文件系统并挂载

[[email protected] ~]# mkfs.xfs /dev/vg1/lv1

[[email protected] ~]# mkfs.ext4 /dev/vg1/lv2

[[email protected] ~]# mkdir /mnt/lv1 /mnt/lv2

[[email protected] ~]# vim /etc/fstab

/dev/vg1/lv1 /mnt/lv1 xfs defaults 0 0

/dev/vg1/lv2 /mnt/lv2 ext4 defaults 0 0

[[email protected] ~]# mount -a

[[email protected] ~]# 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 vgextendpv

[[email protected] ~]# pvcreate /dev/vde

vgextend

[[email protected] ~]# vgextend vg1 /dev/vde

Volume group “vg1” successfully extended

[[email protected] ~]# 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

​ [[email protected] ~]# pvs

​ PV VG Fmt Attr PSize PFree

/dev/vdd vg1 lvm2 a– 2.00g 1.76g

/dev/vde vg1 lvm2 a– 2.00g 2.00gpvmove数据到其它PV

[[email protected] ~]# pvmove /dev/vdd

/dev/vdd: Moved: 16.7%

/dev/vdd: Moved: 100.0%

[[email protected] ~]# 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

vgreduce VG

[[email protected] ~]# vgreduce vg1 /dev/vdd

Removed “/dev/vdd” from volume group “vg1”

[[email protected] ~]# vgs

VG #PV #LV #SN Attr VSize VFree

vg1 1 2 0 wz–n- 2.00g 1.76g

3. LV扩容lv扩容

[[email protected] ~]# vgs

VG #PV #LV #SN Attr VSize VFree

vg1 2 2 0 wz–n- 1.88g 1.00g

[[email protected] ~]# lvextend -L 800M /dev/vg1/lv1

[[email protected] ~]# lvextend -L +800M /dev/vg1/lv1

[[email protected] ~]# lvextend -l 15 /dev/vg1/lv1

[[email protected] ~]# lvextend -l +15 /dev/vg1/lv1

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

+50%FREE

[[email protected] ~]# lvscan

ACTIVE ‘/dev/vg1/lv1’ [768.00 MiB] inherit

ACTIVE ‘/dev/vg1/lv2’ [512.00 MiB] inherit

FS扩容

[[email protected] ~]# 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

[[email protected] ~]# xfs_growfs /dev/vg1/lv1

b. ext2/3/4

[[email protected] ~]# resize2fs /dev/vg1/lv2

[[email protected] ~]# 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创建快照 (EXT4)

[[email protected] ~]# lvcreate -L 128M -s -n lv2-snap /dev/vg1/lv2

[[email protected] ~]# 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

[[email protected] ~]# mount -o ro /dev/vg1/lv2-snap /mnt/lv2-snap/

[[email protected] ~]# 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

[[email protected] ~]# 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

[[email protected] ~]# ls /mnt/lv2

etc lost+found

[[email protected] ~]# ls /mnt/lv2-snap/

etc lost+found

修改原卷的数据

观察Snapshot

[[email protected] ~]# 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：

[[email protected] ~]# 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

[[email protected] ~]# 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：

[[email protected] ~]# vim /etc/lvm/lvm.conf

snapshot_autoextend_threshold = 70

snapshot_autoextend_percent = 20

[[email protected] ~]# systemctl restart lvm2-monitor.service

[[email protected] ~]# systemctl enable lvm2-lvmetad.service

注：快照卷和原卷使用同一VG空间转载请注明来源，欢迎对文章中的引用来源进行考证，欢迎指出任何有错误或不够清晰的表达。可以在下面评论区评论，也可以邮件至 [email protected]