当在linux下编辑某个文件时出现file systems full时，可以用df命令查看磁盘空间使用情况
如果挂载点/的已用%占了100%了，那么就表示/目录(根目录)下已经没有空间了，解决方案：
a.可以考虑把一些.tar包之类的或者上传的压缩包删除掉
b.增加一个虚拟硬盘
操作步骤：
首先，把虚拟机关掉
其次，虚拟机-设置-硬盘sisi-点击添加，去增加硬盘空间
最后，用[root@localhost ~]# fdisk -l 去查看PV NAME(物理卷)的名称，用fdisk -l可能会出现多个pv name(如果之前有增加过虚拟硬盘),可以通过PV size，知道是哪个pv name，这里的pv size就是刚才你增加虚拟硬盘的大小
接着就按照下面的方法一步一步操作
1.查看物理卷
[root@localhost ~]# pvdisplay  //Physical Volume
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup00
  PV Size               3.90 GB / not usable 24.72 MB
  Allocatable           yes (but full)
  PE Size (KByte)       32768
  Total PE              124
  Free PE               0
  Allocated PE          124
  PV UUID               jmRsdv-T0Z5-f0r6-A947-voXX-VGu0-iP60L2
2.将新的磁盘加到物理卷组里面
[root@localhost ~]# pvcreate /dev/sdb  //这个就是通过fdisk -l查到的pv name
  Physical volume "/dev/sdb" successfully created
[root@localhost ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup00
  PV Size               3.90 GB / not usable 24.72 MB
  Allocatable           yes (but full)
  PE Size (KByte)       32768
  Total PE              124
  Free PE               0
  Allocated PE          124
  PV UUID               jmRsdv-T0Z5-f0r6-A947-voXX-VGu0-iP60L2
  
  "/dev/sdb" is a new physical volume of "3.00 GB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb
  VG Name              
  PV Size               3.00 GB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               W5ps21-bKeY-DIw0-FH1K-rVKV-ChwX-1nVzVB

3.查看逻辑卷组//卷组--------VG（Volumn Group）
[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  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               3.88 GB
  PE Size               32.00 MB
  Total PE              124
  Alloc PE / Size       124 / 3.88 GB
  Free  PE / Size       0 / 0  
  VG UUID               7Ar3kU-bSbp-8yrF-3Oo3-vkSE-NDLX-10L0ZI
4.将新增的物理卷 加到卷组里面
[root@localhost ~]# vgextend VolGroup00 /dev/sdb
[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  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               6.84 GB
  PE Size               32.00 MB
  Total PE              219
  Alloc PE / Size       124 / 3.88 GB
  Free  PE / Size       95 / 2.97 GB
  VG UUID               7Ar3kU-bSbp-8yrF-3Oo3-vkSE-NDLX-10L0ZI
这时候看到 逻辑卷组的VG size 已经变成 6.84G了

5.扩展逻辑卷的大小
先df -h 看看 是哪个逻辑卷需要扩容
[root@localhost ~]# df -h
文件系统              容量  已用 可用 已用% 挂载点
/dev/mapper/VolGroup00-LogVol00
                      3.3G  3.3G     0 100% /
/dev/sda1              99M   12M   82M  13% /boot
tmpfs                 125M     0  125M   0% /dev/shm
/dev/hdc              3.8G  3.8G     0 100% /media/CentOS_5.4_Final

“/”分区满了，对应的设备是/dev/mapper/VolGroup00-LogVol00
lvdisplay查看对应的逻辑卷名
[root@localhost ~]# lvdisplay //逻辑卷-----LV（Logical Volume）

  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                ToqjmS-XzO8-Sas0-Bj5d-QCbX-9T8b-83DTNS
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                3.38 GB
  Current LE             108
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
  
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol01
  VG Name                VolGroup00
  LV UUID                gC6Qfo-BgM1-7YC0-9qvB-Z7XT-icjZ-vmFAqq
  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     auto
  - currently set to     256
  Block device           253:1

需要扩容的逻辑卷是/dev/VolGroup00/LogVol00 增加1G 就是自已另外增加的虚拟硬盘大小
[root@localhost ~]# lvextend -L +1G /dev/VolGroup00/LogVol00
  Rounding up size to full physical extent 1.97 GB
  Extending logical volume LogVol00 to 5.34 GB

让上面的扩容生效~
[root@localhost ~]# resize2fs /dev/VolGroup00/LogVol00
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/VolGroup00/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/LogVol00 to 1400832 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 1400832 blocks long.

[root@localhost ~]# df -h
文件系统              容量  已用 可用 已用% 挂载点
/dev/mapper/VolGroup00-LogVol00
                      5.2G  3.3G  1.7G  66% /
/dev/sda1              99M   12M   82M  13% /boot
tmpfs                 125M     0  125M   0% /dev/shm
现在看到 “/” 大小已经变成5.2G了