查看当前LV及PV信息：

[root@rusky ~]# hostnamectl
   Static hostname: localhost.localdomain
Transient hostname: rusky.com
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 9c10c7a9e32e40acb19659a30f73603b
           Boot ID: d20cdc4bccf04de3bc2639830b61a8e6
    Virtualization: kvm
  Operating System: Red Hat Enterprise Linux Server 7.2 (Maipo)
       CPE OS Name: cpe:/o:redhat:enterprise_linux:7.2:GA:server
            Kernel: Linux 3.10.0-327.el7.x86_64
      Architecture: x86-64
------------------------------------------------------------------------------------------------
[root@rusky ~]# pvs
  PV         VG          Fmt  Attr PSize  PFree 
  /dev/sda2  rhel        lvm2 a--   7.51g 40.00m
  /dev/sdb   yum_repo_vg lvm2 a--  15.00g 15.00g    --有一个15G大小的PV，VG名字为yum_repo_vg
[root@rusky ~]# lvs    --有两个默认的LV:root、swap
  LV   VG   Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root rhel -wi-ao----   6.67g                                                    
  swap rhel -wi-ao---- 820.00m                                                    

1. 在名为yum_repo_vg的卷组上创建一个大小为5GB的逻辑卷

[root@rusky ~]# lvcreate -L 5G yum_repo_vg 
  Logical volume "lvol0" created.
[root@rusky ~]# lvs
  LV    VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root  rhel        -wi-ao----   6.67g                                                    
  swap  rhel        -wi-ao---- 820.00m                                                    
  lvol0 yum_repo_vg -wi-a-----   5.00g           

虽然没有用-n指定逻辑卷的名字，但是lvcreate命令会自动命名逻辑卷lvo10.

2. 在名为yum_repo_vg的卷组上创建一个大小为2GB的逻辑卷yum_repo_lvm

[root@rusky ~]# lvcreate -L 2G -n yum_repo_lvm yum_repo_vg 
  Logical volume "yum_repo_lvm" created.
[root@rusky ~]# lvs
  LV           VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root         rhel        -wi-ao----   6.67g                                                    
  swap         rhel        -wi-ao---- 820.00m                                                    
  lvol0        yum_repo_vg -wi-a-----   5.00g                                                    
  yum_repo_lvm yum_repo_vg -wi-a-----   2.00g            

使用-n指定逻辑卷的名字

3. 在名为yum_repo_vg的卷组上创建一个逻辑卷yum_repo_lvm2，大小为50%的VG　

[root@rusky ~]# pvs
  PV         VG          Fmt  Attr PSize  PFree 
  /dev/sda2  rhel        lvm2 a--   7.51g 40.00m
  /dev/sdb   yum_repo_vg lvm2 a--  15.00g  8.00g
[root@rusky ~]# lvcreate -l 50%VG -n yum_repo_lvm2 yum_repo_vg
  Logical volume "yum_repo_lvm2" created.
[root@rusky ~]# lvs
  LV            VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root          rhel        -wi-ao----   6.67g                                                    
  swap          rhel        -wi-ao---- 820.00m                                                    
  lvol0         yum_repo_vg -wi-a-----   5.00g                                                    
  yum_repo_lvm  yum_repo_vg -wi-a-----   2.00g                                                    
  yum_repo_lvm2 yum_repo_vg -wi-a-----   7.50g   ---使用的是50%VG.PSize                 

注意：-l 50%VG是使用PSize的50%，而不是PFree的50%，如果是使用%80VG=12G，大于PFree8G,则报错

4. 在名为yum_repo_vg的卷组上创建一个逻辑卷yum_repo_lvm3，使用全部可用VG空间

[root@rusky ~]# pvs
  PV         VG          Fmt  Attr PSize  PFree  
  /dev/sda2  rhel        lvm2 a--   7.51g  40.00m
  /dev/sdb   yum_repo_vg lvm2 a--  15.00g 512.00m
[root@rusky ~]# lvcreate -l 100%FREE -n yum_repo_lvm3 yum_repo_vg
  Logical volume "yum_repo_lvm3" created.
[root@rusky ~]# lvs
  LV            VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root          rhel        -wi-ao----   6.67g                                                    
  swap          rhel        -wi-ao---- 820.00m                                                    
  lvol0         yum_repo_vg -wi-a-----   5.00g                                                    
  yum_repo_lvm  yum_repo_vg -wi-a-----   2.00g                                                    
  yum_repo_lvm2 yum_repo_vg -wi-a-----   7.50g                                                    
  yum_repo_lvm3 yum_repo_vg -wi-a----- 512.00m   --使用全部的PFee                                                 
[root@rusky ~]# pvs
  PV         VG          Fmt  Attr PSize  PFree 
  /dev/sda2  rhel        lvm2 a--   7.51g 40.00m
  /dev/sdb   yum_repo_vg lvm2 a--  15.00g     0   --PFree为0

原文参考：http://www.ehowstuff.com/4-lvcreate-command-examples-on-linux/