我用虚拟机装的RHEL5.0,虚拟了8G的磁盘,用的自动分区,现在想调整分区大小用df -lh查看了一下,出现:Filesystem Size Used Avail Use% Mounted on/dev/mapper/VolGroup00-LogVol00 6.7G 3.4G 3.0G 54% /再用fdisk -l查看,出现Device boot Start End Blocks Id System/dev/sda2 14 1044 8281507+ 8e Linux LVM请看截图有4问题,请教大家一下:1)/dev/mapper/VolGroup00-LogVol00,这里的挂载点是什么意思,我不太明白???2)我总共只虚拟了8G的磁盘,怎么在/dev/sda2下又出现了8281507 ???3)我没有创建LVM,怎么/dev/sda2的挂载点是linux LVM ???4)如果我想扩充根分区的大小,该怎么创建LVM ???
你用的自动分区方式，系统默认安装的时候选择的是用lvm安装的！
还有你是想调大还是调小，调大的话需要新增加硬盘，调小的话可能数据会造成丢失！
具体怎么调整需要先学习了 lvm后才可以 ！
楼上的,请参见此帖的问题4.-我想扩充根分区的大小.
我的问题你还是没有回答清楚,我想问
1)/dev/mapper/VolGroup00-LogVol00挂载在/分区下,
"mapper/VolGroup00-LogVol00"这些目录指的是什么?为什么我用fdisk -l不能看到它?
2)我刚用vgscan和lvscan查看如下,
这里的LogVol00和LogVol01是不是/分区和swap分区的大小?它们就是LVM的大小?3)我想扩充根分区的大小,该怎么办?
1，/dev/mapper/VoLGroup00-LogVol00，是一个逻辑卷设备 ！这个设备是逻辑设备，不是物理设备，所以不能用fdisk -l来查看，你可以通过 lvdisplay 查看 ！
2，在安装的时候，你先建立了一个 swap空间，剩余的空间系统首先建立一个physical volumes，这个物理卷的大小就应该是你分完swap分区后剩余的大小，然后在physical volumes上创建 volume groups ,最后在volume groups上面创建 logical volumes.这个 /dev/mapper/VoLGroup00-LogVol00就是 logical volumes的名字！
3的意思就是上面我说的 把/dev/sda2分区全部分配给了这个逻辑卷 ！分区的大小你不用太关心，毕竟虚拟机上面分配的大小不是太准确 ！
具体怎么调整逻辑卷的大小可以等晚上回去我发一篇文章，这个一下子不好说 ！
三，Logical Volume Manager(LVM)
creating logical volumes
1,create physical volumes
pvcreate /dev/sda3
2,assign physical volumes to volume groups
vgcreate vg0 /dev/sda3
3,create logical volumes from volume groups
lvcreate -L 256M -n data vg0
mke2fs -j /dev/vg0 data
resizing logical volumes
growing volumes
lvextend: can grow logical volumes
resize2fs: can grow EXT3 filesystems online
vgextend:adds new physical volumes to an existing volume group
shrinking volumes
filesystem must be reduced first
requires a filesystem check and cannot be performed online
lvreduce can then reduce the volume
volume groups can be reduced with:
pvmove /dev/sda4
vgreduce vg0 /dev/sda4
using LVM Snapshosts
1,create snapshot of existing logical volume
#lvcreate -l 64 -s -n databackup /dev/vg0/data
-l: 大小，（PE数量)
-s: 创建快照
-n: 快照名称
2，mount snapshot
#mkdir -p /mnt/databackup
#mount -o ro /dev/vg0/databackup /mnt/databackup
3,remove snapshot
#umount /mnt/databackup
#lvremove /dev/vg0/databackup
例子1：
创建lvm
分区情况：
/dev/sda5 1864 2113 2008093+ 83 Linux
/dev/sda6 2114 2363 2008093+ 83 Linux
/dev/sda7 2364 2613 2008093+ 83 Linux
1,准备物理分区
[root@tonykorn97 ~]# pvcreate /dev/sda5 /dev/sda6
Physical volume "/dev/sda5" successfully created
Physical volume "/dev/sda6" successfully created
2,创建卷组（vg)
[root@tonykorn97 ~]# vgcreate vg0 /dev/sda5 /dev/sda6
Volume group "vg0" successfully created
3,创建逻辑卷(lv)
[root@tonykorn97 ~]# lvcreate -L 256M -n data vg0
Logical volume "data" created
[root@tonykorn97 ~]# mke2fs -j /dev/vg0/data
4,查看逻辑卷状态（pvdisplay,vgdisplay,lvdisplay)：
[root@tonykorn97 ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda5
VG Name vg0
PV Size 1.92 GB / not usable 1.03 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 490
Free PE 426
Allocated PE 64
PV UUID IGrsYz-U1Cd-d2zc-qMZU-mN2F-6lhN-SnurgQ
--- Physical volume ---
PV Name /dev/sda6
VG Name vg0
PV Size 1.92 GB / not usable 1.03 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 490
Free PE 490
Allocated PE 0
PV UUID 42JR9t-eVBb-b10D-J3YB-DwIe-30Tn-A4f1qq
--- Physical volume ---
PV Name /dev/sda2
VG Name vol0
PV Size 13.67 GB / not usable 17.96 MB
Allocatable yes
PE Size (KByte) 32768
Total PE 437
Free PE 165
Allocated PE 272
PV UUID zQcqMn-cl8j-vDJX-q1RK-qZu7-tOOd-U4bhsd
[root@tonykorn97 ~]# vgdisplay
--- Volume group ---
VG Name vg0
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size 3.83 GB
PE Size 4.00 MB
Total PE 980
Alloc PE / Size 64 / 256.00 MB
Free PE / Size 916 / 3.58 GB
VG UUID pVpA1x-0zHs-a2K4-f43m-lgs2-LmHt-wFIylW
--- Volume group ---
VG Name vol0
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 13.66 GB
PE Size 32.00 MB
Total PE 437
Alloc PE / Size 272 / 8.50 GB
Free PE / Size 165 / 5.16 GB
VG UUID mvOUOL-nHtO-aqUo-vM82-27hf-gUw0-iqUAhK
[root@tonykorn97 ~]# lvdisplay
--- Logical volume ---
LV Name /dev/vg0/data
VG Name vg0
LV UUID zJWu4F-3AkP-nGlZ-vivg-g0EM-DrjQ-z80oaa
LV Write Access read/write
LV Status available
# open 0
LV Size 256.00 MB
Current LE 64
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:2
--- Logical volume ---
LV Name /dev/vol0/root
VG Name vol0
LV UUID 2YFBhR-WfBk-JFjy-uRB7-Z1lt-2hVi-62GTED
LV Write Access read/write
LV Status available
# open 1
LV Size 8.00 GB
Current LE 256
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:0
--- Logical volume ---
LV Name /dev/vol0/home
VG Name vol0
LV UUID 7RcMbr-BAXi-kJ3t-5A1P-vqNh-3OuC-bY2qlk
LV Write Access read/write
LV Status available
# open 1
LV Size 512.00 MB
Current LE 16
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:1
[root@tonykorn97 ~]#
例子2：增大逻辑卷的步骤
简单的步骤如下（文件系统没有加载)：
[root@tonykorn97 ~]# lvextend -L +500M /dev/vg0/data
Extending logical volume data to 756.00 MB
Logical volume data successfully resized
[root@tonykorn97 ~]# resize2fs /dev/vg0/data
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vg0/data to 774144 (1k) blocks.
The filesystem on /dev/vg0/data is now 774144 blocks long.
[root@tonykorn97 ~]# lvdisplay
--- Logical volume ---
LV Name /dev/vg0/data
VG Name vg0
LV UUID zJWu4F-3AkP-nGlZ-vivg-g0EM-DrjQ-z80oaa
LV Write Access read/write
LV Status available
# open 0
LV Size 756.00 MB
Current LE 189
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:2
详细步骤：
1,lvextend -L +500M /dev/vg0/data
2,umount /data
3,e2fsck -f /dev/vg0/data
4,resize2fs /dev/vg0/data
5,lvdisplay
例子3，缩小vg的容量大小（一般情况下不要用）
1，umont /data
2,e2fack -f /dev/vg0/data
3,[root@tonykorn97 ~]# resize2fs /dev/vg0/data 100M
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vg0/data to 102400 (1k) blocks.
The filesystem on /dev/vg0/data is now 102400 blocks long.
[root@tonykorn97 ~]#
4,[root@tonykorn97 ~]# lvreduce -L 100M /dev/vg0/data
WARNING: Reducing active logical volume to 100.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce data? [y/n]: y
Reducing logical volume data to 100.00 MB
Logical volume data successfully resized
[root@tonykorn97 ~]#
5,lvdisplay
[root@tonykorn97 ~]# lvdisplay
--- Logical volume ---
LV Name /dev/vg0/data
VG Name vg0
LV UUID zJWu4F-3AkP-nGlZ-vivg-g0EM-DrjQ-z80oaa
LV Write Access read/write
LV Status available
# open 0
LV Size 100.00 MB
Current LE 25
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:2
例子4，增大物理卷组的步骤
1，pvcreate /dev/sda7
2,vgextend vg0 /dev/sda7
3,vgdisplay
原来的状态：
[root@tonykorn97 ~]# vgdisplay
--- Volume group ---
VG Name vg0
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size 3.83 GB
PE Size 4.00 MB
Total PE 980
Alloc PE / Size 25 / 100.00 MB
Free PE / Size 955 / 3.73 GB
创建pv
[root@tonykorn97 ~]# pvcreate /dev/sda7
Physical volume "/dev/sda7" successfully created
扩展vg
[root@tonykorn97 ~]# vgextend vg0 /dev/sda7
Volume group "vg0" successfully extended
查看现在的状态：
[root@tonykorn97 ~]# vgdisplay
--- Volume group ---
VG Name vg0
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 5
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 3
Act PV 3
VG Size 5.74 GB
PE Size 4.00 MB
Total PE 1470
Alloc PE / Size 25 / 100.00 MB
Free PE / Size 1445 / 5.64 GB
VG UUID pVpA1x-0zHs-a2K4-f43m-lgs2-LmHt-wFIylW
例子5，删除逻辑卷
[root@tonykorn97 ~]# lvremove /dev/vg0/data
Do you really want to remove active logical volume "data"? [y/n]: y
Logical volume "data" successfully removed
[root@tonykorn97 ~]#
例子6，删除pv,此时这个分区正在使用，需要先删除vg,然后才可以再删除pv
[root@tonykorn97 ~]# pvremove /dev/sda7
Can't pvremove physical volume "/dev/sda7" of volume group "vg0" without -ff
[root@tonykorn97 ~]# vgremove /dev/vg0
Volume group "vg0" successfully removed
[root@tonykorn97 ~]# pvremove /dev/sda7
Labels on physical volume "/dev/sda7" successfully wiped
[root@tonykorn97 ~]#
不要使用pvremove的-ff参数，使用的话会把vg信息破坏掉。
上面的命令需要删除vg，如果vg中存在内容的话就不能使用，正确的做法是：
[root@tonykorn97 ~]# vgreduce vg0 /dev/sda7
Removed "/dev/sda7" from volume group "vg0"
[root@tonykorn97 ~]# pvremove /dev/sda7
Labels on physical volume "/dev/sda7" successfully wiped
