[root@localhost ~]# free -m
total used free shared buffers cached
Mem: 1877 140 1737 0 6 39
-/+ buffers/cache: 93 1783
Swap: 4143 0 4143
[root@localhost ~]# swapoff -a
[root@localhost ~]# free -m
total used free shared buffers cached
Mem: 1877 136 1740 0 6 39
-/+ buffers/cache: 91 1786
Swap: 0 0 0
使用 lvreduce -L -xxx filename 或 lvreduce -L xxx filename 来减少swap分区空间，“-”代表减多少，不加“-”代表减剩多少。下图表示给swap分区留512M。
使用 mke2fs filename 格式化分区
使用 resize2fs filename 重写分区空间
[root@localhost ~]# lvreduce -L 512M /dev/VolGroup/LogVol01
WARNING: Reducing active and open logical volume to 512.00 MiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce LogVol01? [y/n]: y
Reducing logical volume LogVol01 to 512.00 MiB
Logical volume LogVol01 successfully resized
[root@localhost ~]# mke2fs /dev/VolGroup/LogVol01
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
32768 inodes, 131072 blocks
6553 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=134217728
4 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 29 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@localhost ~]# resize2fs /dev/VolGroup/LogVol01
resize2fs 1.41.12 (17-May-2010)
The filesystem is already 131072 blocks long. Nothing to do!
使用 lvextend -L +1G filename 为根分区增加空闲空间，用法同上。空闲空间可以使用vgdisplay查看，增加空间不需要格式化。
[root@localhost ~]# lvextend -L +3.54G /dev/VolGroup/LogVol00
Rounding size to boundary between physical extents: 3.54 GiB
Extending logical volume LogVol00 to 18.00 GiB
Logical volume LogVol00 successfully resized
[root@localhost ~]# resize2fs /dev/VolGroup/LogVol00
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/VolGroup/LogVol00 is mounted on /; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 2
Performing an on-line resize of /dev/VolGroup/LogVol00 to 4719616 (4k) blocks.
The filesystem on /dev/VolGroup/LogVol00 is now 4719616 blocks long.
swap文件
新建2G的swap文件，挂载到swap,添加到开机启动项。
[root@localhost ~]# dd if=/dev/zero of=/www/swap bs=1024 count=2048000
2048000+0 records in
2048000+0 records out
2097152000 bytes (2.1 GB) copied, 12.0018 s, 175 MB/s
[root@localhost ~]# mkswap /www/swap
mkswap: /www/swap: warning: don't erase bootbits sectors
on whole disk. Use -f to force.
Setting up swapspace version 1, size = 2047996 KiB
no label, UUID=92ab4ed5-f301-4ba4-970f-9e5600610522
[root@localhost ~]# swapon /www/swap
[root@localhost ~]# free -m
total used free shared buffers cached
Mem: 1877 1796 80 0 7 1647
-/+ buffers/cache: 142 1735
Swap: 1999 0 1999
[root@localhost ~]# swapon -s
Filename Type Size Used Priority
/www/swap file 2047992 0 -1
修改启动项
编辑 /etc/fstab文件，去掉之前的swap分区挂载，在最末行增加swap文件的挂载
[root@localhost ~]# cat /etc/fstab