linux LVM 常用总结

1 创建、删除思路

创建：Linux分区---物理卷---卷组---逻辑卷--文件系统

删除：卸载文件系统---逻辑卷---卷组----物理卷---Linux分区

2 linux分区

linux中我们通常使用fdisk对磁盘做分区操作，但它只能划分2T以下的磁盘，而现在大于2T的磁盘很常见。这个时候我们使用parted命令对磁盘做分区操作，以下用于学习parted命令

1）GPT 磁盘和 MBR磁盘

利用parted命令可以对GPT磁盘分区，GPT格式的磁盘相当于原来MBR磁盘中原来保留4个partition table的4*16个字节，只留第一个16个字节，类似于扩展分区，GPT磁盘没有四个主分区的限制,可以设置多达128个分区

2)操作

--查看sda原先分区

[root@mytest07 ~]# fdisk -l

Disk /dev/sda: 107.4 GB, 107374182400 bytes, 209715200 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 label type: dos

Disk identifier: 0x000cc025

Device Boot Start End Blocks Id System

/dev/sda1 * 2048 4196351 2097152 83 Linux

/dev/sda2 4196352 100681727 48242688 8e Linux LVM

/dev/sda3 100681728 117187500 8252886+ 8e Linux LVM

/dev/sda4 117187501 126953125 4882812+ f W95 Ext'd (LBA)

[root@mytest07 ~]# parted /dev/sda --对sda进行分区

GNU Parted 3.1

Using /dev/sda

Welcome to GNU Parted! Type 'help' to view a list of commands.

(parted) help

align-check TYPE N check partition N for TYPE(min|opt) alignment

help [COMMAND] print general help, or help on COMMAND

mklabel,mktable LABEL-TYPE create a new disklabel (partition table)

mkpart PART-TYPE [FS-TYPE] START END make a partition

name NUMBER NAME name partition NUMBER as NAME

print [devices|free|list,all|NUMBER] display the partition table, available devices, free space, all found

partitions, or a particular partition

quit exit program

rescue START END rescue a lost partition near START and END

rm NUMBER delete partition NUMBER

select DEVICE choose the device to edit

disk_set FLAG STATE change the FLAG on selected device

disk_toggle [FLAG] toggle the state of FLAG on selected device

set NUMBER FLAG STATE change the FLAG on partition NUMBER

toggle [NUMBER [FLAG]] toggle the state of FLAG on partition NUMBER

unit UNIT set the default unit to UNIT

version display the version number and copyright information of GNU Parted

(parted) p --打印当前分区情况

Model: VMware Virtual disk (scsi)

Disk /dev/sda: 107GB

Sector size (logical/physical): 512B/512B

Partition Table: msdos

Disk Flags:

Number Start End Size Type File system Flags

1 1049kB 2149MB 2147MB primary xfs boot

2 2149MB 51.5GB 49.4GB primary lvm

3 51.5GB 60.0GB 8451MB primary lvm

4 60.0GB 65.0GB 5000MB extended lba

(parted) rm 4 --删除分区3、4

(parted) rm 3

(parted) mkpart primary 51500 60000 --创建新分区从 51.5G 到60G

Warning: You requested a partition from 51.5GB to 60.0GB (sectors 100585937..117187500).

The closest location we can manage is 51.5GB to 60.0GB (sectors 100681728..117187500).

Is this still acceptable to you?

Yes/No? y

(parted) p

Model: VMware Virtual disk (scsi)

Disk /dev/sda: 107GB

Sector size (logical/physical): 512B/512B

Partition Table: msdos

Disk Flags:

Number Start End Size Type File system Flags

1 1049kB 2149MB 2147MB primary xfs boot

2 2149MB 51.5GB 49.4GB primary lvm

3 51.5GB 60.0GB 8451MB primary

(parted) set 3 lvm on --设置分区为lvm类型

(parted) q

Information: You may need to update /etc/fstab.

[root@mytest07 ~]# partprobe --重新扫描分区

Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only.

[root@mytest07 ~]# fdisk -l --查看分区后

Disk /dev/sda: 107.4 GB, 107374182400 bytes, 209715200 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 label type: dos

Disk identifier: 0x000cc025

Device Boot Start End Blocks Id System

/dev/sda1 * 2048 4196351 2097152 83 Linux

/dev/sda2 4196352 100681727 48242688 8e Linux LVM

/dev/sda3 100681728 117187500 8252886+ 8e Linux LVM

3 物理卷的管理

1）创建物理卷：pvcreate

[root@mytest07 ~]# pvcreate /dev/sda3

Physical volume "/dev/sda3" successfully created.

2）查看当前物理卷信息：pvs或pvscan

[root@mytest07 ~]# pvs

PV VG Fmt Attr PSize PFree

/dev/sda2 rhel lvm2 a-- 46.00g 4.00m

/dev/sda3 lvm2 --- 7.87g 7.87g

3）查看物理卷详细信息:pvdiskplay pvname

[root@mytest07 ~]# pvdisplay /dev/sda3

"/dev/sda3" is a new physical volume of "7.87 GiB"

--- NEW Physical volume ---

PV Name /dev/sda3

VG Name

PV Size 7.87 GiB

Allocatable NO

PE Size 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID EpUIK3-k9Tj-6laD-fDGI-LGRu-VlAi-MBjq6d

4）删除物理卷：pvremove

[root@mytest07 ~]# pvremove /dev/sda3

Labels on physical volume "/dev/sda3" successfully wiped.

4卷组的管理

1) 创建卷组

创建格式：vgcreate [-s <8M|16M|...>] vg0 /dev/sdb{1,2,3...} -s：指定扩展块（PE）的大小，默认为4MB；（相当与磁盘上的簇，扩展逻辑卷的基本单位。后面的值可以是8M 16M 32M 64M .....最多65532个扩展块。vg0：新创建的卷组的名字。/dev/sdb{1,2,3...}：需要的物理卷可以写多个；

[root@mytest07 ~]# vgcreate -s 16M testvg /dev/sda3

Volume group "testvg" successfully created

2）查看当前系统信息

[root@mytest07 ~]# vgs

VG #PV #LV #SN Attr VSize VFree

rhel 1 3 0 wz--n- 46.00g 4.00m

testvg 1 0 0 wz--n- 7.86g 7.86g

3）查看当前卷组详细信息

[root@mytest07 ~]# vgdisplay testvg

--- Volume group ---

VG Name testvg

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 7.86 GiB

PE Size 16.00 MiB

Total PE 503

Alloc PE / Size 0 / 0

Free PE / Size 503 / 7.86 GiB

VG UUID ywd9ae-AVf5-LWl1-WuYM-xk95-KzsS-aVCanx

4）vg扩展

[root@mytest07 ~]# fdisk /dev/sda --此处用fdisk划分区

Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

Command (m for help): n

Partition type:

p primary (3 primary, 0 extended, 1 free)

e extended

Select (default e): e

Selected partition 4

First sector (117187501-209715199, default 117188608):

Using default value 117188608

Last sector, +sectors or +size{K,M,G} (117188608-209715199, default 209715199):

Using default value 209715199

Partition 4 of type Extended and of size 44.1 GiB is set

Command (m for help): p

Disk /dev/sda: 107.4 GB, 107374182400 bytes, 209715200 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 label type: dos

Disk identifier: 0x000cc025

Device Boot Start End Blocks Id System

/dev/sda1 * 2048 4196351 2097152 83 Linux

/dev/sda2 4196352 100681727 48242688 8e Linux LVM

/dev/sda3 100681728 117187500 8252886+ 8e Linux LVM

/dev/sda4 117188608 209715199 46263296 5 Extended

Command (m for help): n

All primary partitions are in use

Adding logical partition 5

First sector (117190656-209715199, default 117190656):

Using default value 117190656

Last sector, +sectors or +size{K,M,G} (117190656-209715199, default 209715199): +20G

Partition 5 of type Linux and of size 20 GiB is set

Command (m for help): t --改分区类型为lvm

Partition number (1-5, default 5):

Hex code (type L to list all codes): 8e

Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.

The kernel still uses the old table. The new table will be used at

the next reboot or after you run partprobe(8) or kpartx(8)

Syncing disks.

[root@mytest07 ~]# fdisk -l

Disk /dev/sda: 107.4 GB, 107374182400 bytes, 209715200 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 label type: dos

Disk identifier: 0x000cc025

Device Boot Start End Blocks Id System

/dev/sda1 * 2048 4196351 2097152 83 Linux

/dev/sda2 4196352 100681727 48242688 8e Linux LVM

/dev/sda3 100681728 117187500 8252886+ 8e Linux LVM

/dev/sda4 117188608 209715199 46263296 5 Extended

/dev/sda5 117190656 159133695 20971520 8e Linux LVM

Disk /dev/mapper/rhel-root: 42.9 GB, 42949672960 bytes, 83886080 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/rhel-swap: 2147 MB, 2147483648 bytes, 4194304 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/rhel-var: 4294 MB, 4294967296 bytes, 8388608 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@mytest07 ~]# partprobe --重新扫描分区

Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only.

[root@mytest07 ~]# pvcreate /dev/sda5 --创建物理卷

Physical volume "/dev/sda5" successfully created.

[root@mytest07 ~]# vgextend testvg /dev/sda5 --扩展vg

Volume group "testvg" successfully extended

5）vg缩小

[root@mytest07 ~]# vgreduce testvg /dev/sda5

Removed "/dev/sda5" from volume group "testvg"

6）vg删除

[root@mytest07 ~]# vgremove testvg

Volume group "testvg" successfully removed

5 逻辑卷的管理

1）逻辑卷的创建

格式1：lvcreate -L 512M -n data testvg -L 512M：设置逻辑卷的大小为512M。 -n data：设置逻辑卷的名字为data ；表示法：/dev/卷组名/data/testvg:设置是有那个卷组生成的逻辑卷。

[root@mytest07 ~]# lvcreate -L 510M -n date testvg

Rounding up size to full physical extent 512.00 MiB

Logical volume "date" created.

格式2：lvcreate -l 32 -n data testvg -l 32：生成的逻辑卷使用32个扩展块，逻辑卷大小=32*PE（默认4M）则为128M -n data：逻辑卷的名字； vg0 ：设置是有那个卷组生成的逻辑卷。 [root@mytest07 ~]# lvcreate -l 10 -n data testvg

Logical volume "data" created.

2) 查看逻辑卷:lvs或者lvscan

[root@mytest07 ~]# lvs

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

root rhel -wi-ao---- 40.00g

swap rhel -wi-ao---- 2.00g

var rhel -wi-ao---- 4.00g

data testvg -wi-a----- 160.00m

date testvg -wi-a----- 512.00m

3）查看逻辑卷详细信息

[root@mytest07 ~]# lvdisplay testvg

--- Logical volume ---

LV Path /dev/testvg/date

LV Name date

VG Name testvg

LV UUID dGmhX5-AYbF-QVo4-iNPF-Br82-eBvJ-h4Asep

LV Write Access read/write

LV Creation host, time mytest07, 2018-04-19 13:47:55 +0800

LV Status available

# open 0

LV Size 512.00 MiB

Current LE 32

Segments 1

Allocation inherit

Read ahead sectors auto

- currently set to 8192

Block device 253:3

4）格式化逻辑卷

[root@mytest07 ~]# mkfs.ext3 /dev/testvg/data

5）增大逻辑卷：lvextend

格式:lvextend -L +160M /dev/testvg/data

需要额外的命令使立即生效：resize2fs

resize2fs /dev/testvg/data

6）减少逻辑卷大小:lvreduce

[root@mytest07 dev]# lvreduce -L 160M /dev/testvg/data

resize2fs /dev/testvg/data

7)删除逻辑卷：lvremove/卷组名/逻辑卷名

[root@mytest07 dev]# lvremove /dev/testvg/date

6挂载文件系统

[root@mytest07 ~]# mkfs.ext3 /dev/testvg/data

[root@mytest07 dev]# mkdir /data

[root@mytest07 dev]# mount /dev/testvg/data /data

7 lvm快照

1）快照的创建

格式：Lvcreate -l 64 -s -n databackup /dev/testvg/data

-l 64：之前我们已经说过了这里是 64个扩展块，总容量=64*单扩展块大小 -n databackup：生成的快照的名字。 /dev/testvg/data：源逻辑卷名字。

[root@mytest07 dev]# lvcreate -L 160M -s -n databackup /dev/testvg/data

Using default stripesize 64.00 KiB

2）查看

[root@mytest07 dev]# lvscan

ACTIVE '/dev/rhel/root' [40.00 GiB] inherit

ACTIVE '/dev/rhel/var' [4.00 GiB] inherit

ACTIVE '/dev/rhel/swap' [2.00 GiB] inherit

ACTIVE Original '/dev/testvg/data' [160.00 MiB] inherit

ACTIVE Snapshot '/dev/testvg/databackup' [160.00 MiB] inherit

3）快照详细信息查看

[root@mytest07 dev]# lvdisplay /dev/testvg/data

4）快照的删除：lvremove snapshotname

[root@mytest07 dev]# lvremove /dev/testvg/databackup

linux LVM 常用总结