LVM概念
啥是LVM？。Logical Volume Manager中文名叫逻辑卷管理器，简称LVM，它是Linux下对逻辑卷进行管理的一套程序，LVM分区，就是LVM管理下的一个逻辑卷。LVM通常涉及下面几个术语：
- PP（physical Partition）
物理分区，通常指硬盘中的主分区，逻辑分区。严格来讲整个硬盘或者其他能存东西的物理介质包括网络存储也能作为一个物理分区，但一定是有实物的 - PV（Physical Volume）
物理卷，就是在PP（物理分区）的基础上，使用pvcreate指令写入一些数据，转换为可供LVM识别后的物理介质。 - VG（Volumes Group）
卷组，由一个或多个PV组成的一个分组，形成一大块存储空间 - LV（Logical Volume）
逻辑卷，也就是LVM分区，在VG上划分一块空间称为逻辑卷，一个VG上只要还有空间就可以建立多个LV。在逻辑卷之上可以建立文件系统(ext3、ext4等)，然后即可把数据存到分区里 - PE（Physical Extent）
具有唯一编号的PE是可以被LVM寻址的最小单元，其大小是在创建VG时确定的，默认为4MB(可通过vgcreate -s指定)。一个VG包含N个PE，从VG上划分一块空间作为LV时就是把其中一部分数量的PE标记为该LV。
LVM分区扩容
LVM分区扩容实际上是扩容LV分区的大小，配置思路如下：
fdisk创建lvm类型分区 -> 使用该分区创建PV -> PV加入VG，扩容VG -> 扩容LV分区 -> 刷新分区大小fdisk新建分区
在esxi后台对硬盘扩容后，并不会直接应用到系统中，需要将扩容的区块新建为系统分区。
配置思路： 创建主分区 -> 设置分区类型为8e（lvm类型） -> 保存分区一些问题：如果创建的第一个分区没达到目标容量，是开始和结束的块选择到了非预期扩容的区域。取巧的方法可多创建几个分区（不能保存）， 直到获得的目标分区符合实际大小，之后删除无用的分区即可。
关键命令介绍
Command (m for help): n使用n指令创建分区，选p创建主分区；
Partition number (3,4, default 3)设置主分区id为3，即sda3，这里我创建两个分区sda3 sda4,sda3不是目标分区后续要删除（因为要使用sd4的块就必须先创建sda3）；
Command (m for help): t使用t指令修改分区的类型；
Partition number (1-5): 4选择要修改的分区id；
Hex code (type L to list codes): 8e选择分区的类型(8e就表示lvm)，输入l可列出所有支持的类型；
Command (m for help): p现在打印一下当前分区表，确认是不是自己想要的；
Command (m for help): w确认分区表正确后，用w写入硬盘。
partprobe刷新分区表。
配置记录
root@debian:~# fdisk /dev/sda
Welcome to fdisk (util-linux 2.33.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): p
Disk /dev/sda: 60 GiB, 64424509440 bytes, 125829120 sectors
Disk model: Virtual disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x745f4409
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 41940991 40939522 19.5G 5 Extended
/dev/sda5 1001472 41940991 40939520 19.5G 8e Linux LVM
Command (m for help): n
Partition type
p primary (1 primary, 1 extended, 2 free)
l logical (numbered from 5)
Select (default p): p
Partition number (3,4, default 3): 3
First sector (999424-125829119, default 999424):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (999424-1001469, default 1001469):
Created a new partition 3 of type 'Linux' and of size 1023 KiB.
Command (m for help): p
Disk /dev/sda: 60 GiB, 64424509440 bytes, 125829120 sectors
Disk model: Virtual disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x745f4409
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 41940991 40939522 19.5G 5 Extended
/dev/sda3 999424 1001469 2046 1023K 83 Linux
/dev/sda5 1001472 41940991 40939520 19.5G 8e Linux LVM
Partition table entries are not in disk order.
Command (m for help): n
Partition type
p primary (2 primary, 1 extended, 1 free)
l logical (numbered from 5)
Select (default p): p
Selected partition 4
First sector (41940992-125829119, default 41940992):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (41940992-125829119, default 125829119):
Created a new partition 4 of type 'Linux' and of size 40 GiB.
Command (m for help):
Command (m for help): p
Disk /dev/sda: 60 GiB, 64424509440 bytes, 125829120 sectors
Disk model: Virtual disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x745f4409
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 41940991 40939522 19.5G 5 Extended
/dev/sda3 999424 1001469 2046 1023K 83 Linux
/dev/sda4 41940992 125829119 83888128 40G 83 Linux
/dev/sda5 1001472 41940991 40939520 19.5G 8e Linux LVM
Partition table entries are not in disk order.
Command (m for help): d
Partition number (1-5, default 5): 3
Partition 3 has been deleted.
Command (m for help): p
Disk /dev/sda: 60 GiB, 64424509440 bytes, 125829120 sectors
Disk model: Virtual disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x745f4409
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 41940991 40939522 19.5G 5 Extended
/dev/sda4 41940992 125829119 83888128 40G 83 Linux
/dev/sda5 1001472 41940991 40939520 19.5G 8e Linux LVM
Partition table entries are not in disk order.
Command (m for help): t
Partition number (1,2,4,5, default 5): 4
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'.
Command (m for help): p
Disk /dev/sda: 60 GiB, 64424509440 bytes, 125829120 sectors
Disk model: Virtual disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x745f4409
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 41940991 40939522 19.5G 5 Extended
/dev/sda4 41940992 125829119 83888128 40G 8e Linux LVM
/dev/sda5 1001472 41940991 40939520 19.5G 8e Linux LVM
Partition table entries are not in disk order.
Command (m for help):
Command (m for help): w
The partition table has been altered.
Syncing disks.
root@debian:~# fdisk -l
Disk /dev/sda: 60 GiB, 64424509440 bytes, 125829120 sectors
Disk model: Virtual disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x745f4409
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 41940991 40939522 19.5G 5 Extended
/dev/sda4 41940992 125829119 83888128 40G 8e Linux LVM
/dev/sda5 1001472 41940991 40939520 19.5G 8e Linux LVM
Partition table entries are not in disk order.
Disk /dev/mapper/debian--vg-root: 18.6 GiB, 19931332608 bytes, 38928384 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 /dev/mapper/debian--vg-swap_1: 980 MiB, 1027604480 bytes, 2007040 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
root@debian:~#
root@debian:~# partprobe
root@debian:~# 创建PV
/dev/sda4 为上一步新增的分区
root@debian:~# pvcreate /dev/sda4
Physical volume "/dev/sda4" successfully created.PV表示的是一个个物理分区，需要加入到VG中，扩容VG的容量。
扩容VG
vgdisplay查看当前的VG详情
root@debian:~# vgdisplay
--- Volume group ---
VG Name debian-vg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size <19.52 GiB
PE Size 4.00 MiB
Total PE 4997
Alloc PE / Size 4997 / <19.52 GiB
Free PE / Size 0 / 0
VG UUID 2FWOSr-RBUZ-lUd5-ATV5-Jf3i-mpeR-QQ325A
将创建的pv加入VG中。
root@debian:~# vgextend debian-vg /dev/sda4
Volume group "debian-vg" successfully extended查看VG容量增加了。
root@debian:~# vgdisplay
--- Volume group ---
VG Name debian-vg
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 <59.52 GiB
PE Size 4.00 MiB
Total PE 15237
Alloc PE / Size 4997 / <19.52 GiB
Free PE / Size 10240 / 40.00 GiB
VG UUID 2FWOSr-RBUZ-lUd5-ATV5-Jf3i-mpeR-QQ325A扩容LV
查看现有的LV，同一个VG中可以有多个LV，这里扩容/dev/debian-vg/root。
root@debian:~# lvdisplay -l
lvdisplay: invalid option -- 'l'
Error during parsing of command line.
root@debian:~# lvdisplay
--- Logical volume ---
LV Path /dev/debian-vg/root
LV Name root
VG Name debian-vg
LV UUID WT5yLx-vEpt-IVDo-UEDw-W3mh-rGQl-xGo1Uo
LV Write Access read/write
LV Creation host, time debian, 2021-12-19 11:06:39 +0800
LV Status available
# open 1
LV Size 58.56 GiB
Current LE 14992
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:0
--- Logical volume ---
LV Path /dev/debian-vg/swap_1
LV Name swap_1
VG Name debian-vg
LV UUID eBkgqj-hFEo-sMOh-3tRc-rjef-EwTh-ulflUC
LV Write Access read/write
LV Creation host, time debian, 2021-12-19 11:06:39 +0800
LV Status available
# open 2
LV Size 980.00 MiB
Current LE 245
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:1扩容/dev/mapper/debian--vg-root
root@debian:~# lvextend -l +100%FREE /dev/mapper/debian--vg-root
Size of logical volume debian-vg/root changed from 18.56 GiB (4752 extents) to 58.56 GiB (14992 extents).
Logical volume debian-vg/root successfully resized.刷新分区大小
使用resize2fs刷新对应分区即可。
root@debian:~# resize2fs /dev/mapper/debian--vg-root
resize2fs 1.44.5 (15-Dec-2018)
Filesystem at /dev/mapper/debian--vg-root is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 8
The filesystem on /dev/mapper/debian--vg-root is now 15351808 (4k) blocks long.
root@debian:~# df -h
Filesystem Size Used Avail Use% Mounted on
udev 3.9G 0 3.9G 0% /dev
tmpfs 798M 8.8M 790M 2% /run
/dev/mapper/debian--vg-root 58G 8.7G 47G 16% /
/dev/sda1 470M 83M 363M 19% /boot拓展
未分区的磁盘扩容
在esxi直接扩容虚拟机硬盘后，直接进入系统刷新磁盘大小即可。
root@debian:~# resize2fs /dev/sdb
resize2fs 1.44.5 (15-Dec-2018)
Filesystem at /dev/sdb is mounted on /mnt/data; on-line resizing required
old_desc_blocks = 38, new_desc_blocks = 75
The filesystem on /dev/sdb is now 157286400 (4k) blocks long.