由于系统部署的时候，分区使用的默认分区管理，系统规划不是很好，swap过于大，浪费了很多磁盘空间，这里讲将swap下线，进行缩容，然后将缩减出的容量补充到在线的根分区上。固然只有一个根分区不好，这样规划以后会出一些问题，这里只讨论操作的扩缩的操作步骤。
下文中，红色加粗字体的部分是操作的命令，蓝色部分是需要特别注意的地方。通过这些蓝色的输出来确定你的服务器该怎么调整容量大小，并且检查是否达到调整的预期。
思路：首先查看swap的大小及分区，然后调整swap大小，使vg中有空余的空间可以给根分区的lv进行补充。然后重建swap，挂载swap，检查vg的空余容量显示是否正常，然后给根分区的lv扩容，resize2fs，完成。
此操作为真实线上服务器的调整记录，供朋友们参考，在真实上线操作之前，请务必在与你在的平台完全相同的实验环境进行详细的测试，然后方可实施操作。我的系统环境是：
操作系统：RHEL 5u3 64bit
内核版本：2.6.18-128.el5
[root@server10 ~]# free -g
total used free shared buffers cached
Mem: 62 62 0 0 0 60
-/+ buffers/cache: 2 60
Swap: 127 0 127
[root@server10 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
147G 74G 65G 54% /
/dev/sda1 99M 13M 81M 14% /boot
tmpfs 32G 0 32G 0% /dev/shm
[root@server10 ~]# cat /etc/fstab
/dev/VolGroup00/LogVol00 / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/VolGroup00/LogVol01 swap swap defaults 0 0
[root@server10 ~]# lvdisplay
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID oZ7rEm-hphT-MsGk-fNaD-RC5X-INgZ-oCJdml
LV Write Access read/write
LV Status available
# open 1
LV Size 150.84 GB
Current LE 4827
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 pCpqVB-cwXV-MunF-OtBQ-usYA-hFxt-l07IJc
LV Write Access read/write
LV Status available
# open 1
LV Size 127.91 GB
Current LE 4093
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
[root@server10 ~]# 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 278.75 GB
PE Size 32.00 MB
Total PE 8920
Alloc PE / Size 8920 / 278.75 GB
Free PE / Size 0 / 0
VG UUID 9hHRZZ-VUd4-bMwc-rnhK-wiyq-sPZw-dtJREo
[root@server10 ~]# free -m
total used free shared buffers cached
Mem: 64449 64129 320 0 327 61494
-/+ buffers/cache: 2307 62142
Swap: 130975 0 130975
[root@server10 ~]# swapoff -a
[root@server10 ~]# free -m
total used free shared buffers cached
Mem: 64449 64065 384 0 327 61494
-/+ buffers/cache: 2243 62206
Swap: 0 0 0
[root@server10 ~]# lvreduce /dev/VolGroup00/LogVol01 -L -64G
WARNING: Reducing active logical volume to 63.91 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce LogVol01? [y/n]: y
Reducing logical volume LogVol01 to 63.91 GB
Logical volume LogVol01 successfully resized
[root@server10 ~]# mkswap /dev/VolGroup00/LogVol01
Setting up swapspace version 1, size = 68618809 kB
[root@server10 ~]# swapon /dev/VolGroup00/LogVol01
[root@server10 ~]# free -m
total used free shared buffers cached
Mem: 64449 64150 299 0 327 61549
-/+ buffers/cache: 2273 62175
Swap: 65439 0 65439
[root@server10 ~]# free -g
total used free shared buffers cached
Mem: 62 62 0 0 0 60
-/+ buffers/cache: 2 60
Swap: 63 0 63
[root@server10 ~]# vgdisplay
--- Volume group ---
VG Name VolGroup00
System ID
Format lvm2
Metadata Areas 1
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 1
Act PV 1
VG Size 278.75 GB
PE Size 32.00 MB
Total PE 8920
Alloc PE / Size 6872 / 214.75 GB
Free PE / Size 2048 / 64.00 GB
VG UUID 9hHRZZ-VUd4-bMwc-rnhK-wiyq-sPZw-dtJREo
[root@server10 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
147G 74G 65G 54% /
/dev/sda1 99M 13M 81M 14% /boot
tmpfs 32G 0 32G 0% /dev/shm
[root@server10 ~]# mount
/dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
[root@server10 ~]# lvextend /dev/VolGroup00/LogVol00 -l +100%FREE
Extending logical volume LogVol00 to 214.84 GB
Logical volume LogVol00 successfully resized
[root@server10 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
147G 74G 65G 54% /
/dev/sda1 99M 13M 81M 14% /boot
tmpfs 32G 0 32G 0% /dev/shm
[root@server10 ~]# 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 56320000 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 56320000 blocks long.
[root@server10 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
209G 74G 124G 38% /
/dev/sda1 99M 13M 81M 14% /boot
tmpfs 32G 0 32G 0% /dev/shm
[root@server10 ~]#