系统中有一个sda2是linux lvm格式的，对应了一个lvm的逻辑卷，怎么实现sda2对应二个或者多个逻辑卷呢，详细操作过程如下：
前面二篇文章，也是有关LVM的，每一步都说的很清楚，有兴趣的可以看一下
[root@localhost ~]# df -h //缩小空间前
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 356G 39G 299G 12% /
tmpfs 3.9G 72K 3.9G 1% /dev/shm
/dev/sda1 485M 40M 420M 9% /boot
/dev/mapper/VolGroup-lv_home 99G 23G 72G 22% /home
[root@localhost ~]# umount /home/ //取消挂载
[root@localhost ~]# e2fsck -f /dev/mapper/VolGroup-lv_home //磁盘检测
e2fsck 1.41.12 (17-May-2010)
第一步: 检查inode,块,和大小
第二步: 检查目录结构
第3步: 检查目录连接性
Pass 4: Checking reference counts
第5步: 检查簇概要信息
/dev/mapper/VolGroup-lv_home: 1580/5898240 files (4.4% non-contiguous), 6244001/23592960 blocks
[root@localhost ~]# resize2fs -p /dev/mapper/VolGroup-lv_home 85G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/VolGroup-lv_home to 22282240 (4k) blocks.
Begin pass 3 (max = 720)
正在扫描inode表 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/VolGroup-lv_home is now 22282240 blocks long.
[root@localhost ~]# mount /home/ //在挂上去
[root@localhost ~]# df -h //在看一下，分区情况
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 356G 39G 299G 12% /
tmpfs 3.9G 72K 3.9G 1% /dev/shm
/dev/sda1 485M 40M 420M 9% /boot
/dev/mapper/VolGroup-lv_home 84G 23G 58G 29% /home //变小了
[root@localhost ~]# lvreduce -L 85G /dev/mapper/VolGroup-lv_home //减小home分区
WARNING: Reducing active and open logical volume to 85.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv_home? [y/n]: y
Reducing logical volume lv_home to 85.00 GiB
Logical volume lv_home successfully resized
[root@localhost ~]# vgdisplay //查看一下逻辑卷组的情况
--- Volume group ---
VG Name VolGroup
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 7
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 465.27 GiB
PE Size 4.00 MiB
Total PE 119109
Alloc PE / Size 115269 / 450.27 GiB
Free PE / Size 3840 / 15.00 GiB //有可用空间3840个PE，15GB
VG UUID Vt2V4t-Byxs-tQqk-cY0h-IDE3-pabX-LUfkRS
//用VolGroup卷组中所有可用空间，创建逻辑卷tanktest卷，下午列举几个常用的
[root@localhost ~]# lvcreate --name tanktest -l 100%FREE VolGroup
Logical volume "tanktest" created
//在VolGroup卷组中创建一个200M逻辑卷tanktest1
[root@localhost ~]# lvcreate -L 200 -n tanktest1 VolGroup
//在VolGroup卷组中创建一个20G逻辑卷tanktest2
[root@localhost ~]# lvcreate -L 20G -n tanktest2 VolGroup
//用VolGroup卷组中50%的可用空间,创建逻辑卷tanktest3
[root@localhost ~]# lvcreate -l 50%VG -n tanktest3 VolGroup
[root@localhost ~]# mkdir /mnt/tanktest //创建挂载目录
[root@localhost ~]# mkfs.ext4 /dev/VolGroup/tanktest //格式化新建的逻辑卷tanktest
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=1 blocks, Stripe width=0 blocks
983040 inodes, 3932160 blocks
196608 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=4026531840
120 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208
正在写入inode表: 完成
Creating journal (32768 blocks): 完成
Writing superblocks and filesystem accounting information: 完成
This filesystem will be automatically checked every 27 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@localhost ~]# echo '/dev/VolGroup/tanktest /mnt/tanktest ext4 defaults 0 0' >> /etc/fstab //自动挂载
[root@localhost ~]# reboot //重启，检测一下是不是能自动挂载
[root@localhost ~]# df -h //查看分区情况，新逻辑卷已正确挂载
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 356G 40G 298G 12% /
tmpfs 3.9G 0 3.9G 0% /dev/shm
/dev/sda1 485M 40M 420M 9% /boot
/dev/mapper/VolGroup-lv_home 84G 23G 58G 29% /home
/dev/mapper/VolGroup-tanktest 15G 166M 14G 2% /mnt/tanktest
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